1998 E-Series Workshop Manual

Transcription

1 SECTION A: Anti-Lock Control Rear DIAGNOSIS AND TESTING Procedure revision date: 02/08/2000 Anti-Lock Control Refer to Wiring Diagrams Cell 42, Speed Control for schematic and connector information. Special Tool(s) 73 Digital Multimeter or equivalent 105-R0051 Inspection and Verification NOTE: Check the integrity of all connectors and their associated harnesses. Be sure to check for the following: Frayed wires. Loose or damaged connectors. Damaged wire harness. Dirt or foreign matter in connections. Warning indicator bulb(s). System Pre-Check NOTE: Perform this procedure first. Failure to do so can result in incorrect diagnosis of a problem, wasted time, and improper replacement of components. The system pre-check screens a vehicle for relatively simple diagnostic repairs, such as loose connectors, blown fuses, etc. However, the system pre-check also prepares the vehicle for further diagnostics. In addition, warning indicator concerns are diagnosed in this test. NOTE: The anti-lock brake control module is commonly referred to as the RABS II module. This repair procedure is written for REAR ABS II (RABS II) systems. The RABS II system is standard for Econoline vehicles, except E-Super Duty. The RABS II uses the instrument panel yellow ABS warning indicator and under some conditions the red BRAKE warning indicator to alert the driver to a system malfunction. Both warning indicators must be working properly to assist in diagnosis. The steps below must be followed prior to beginning the RABS II diagnostic procedure. Vehicle Setup WARNING: Place blocks behind the rear wheels (1007) and in front of the front wheels to prevent the vehicle from moving while the system pre-check is being done. Drive the vehicle to a level area, and place the shift lever in PARK for automatic transmissions (7003). Turn the ignition off, set the parking brake and turn on the running lamps. Place blocks behind the rear wheels and in front of the front wheels. Release the parking brake. Warning Indicator Lamp The red BRAKE warning indicator is constantly monitored by the anti-lock brake control module. If the red BRAKE warning indicator illuminates, the anti-lock brake control module will disable the RABS II system and turn on the yellow ABS warning indicator. For this reason, diagnosing and resolving any base brake concerns illuminating the red BRAKE warning indicator will, in most cases, resolve a perceived RABS II concern. Red BRAKE Warning Indicator Self Check The red BRAKE warning indicator is used to indicate a low fluid level condition or parking brake applied condition. To check this warning indicator, insert the key in the ignition switch (11572) and turn it to the START position. The warning indicator should illuminate with the key in the START position. If it fails to illuminate, go to Symptom Chart. Allow the key to spring back from the START position to the RUN position. At this time, the red BRAKE warning indicator should turn off. If it does not turn off, recheck the parking brake switch to make sure that it is fully disengaged. In the event that the red BRAKE warning indicator remains on, go to Symptom Chart. Yellow ABS Warning Indicator Self Check The yellow ABS warning indicator is used to indicate a malfunction and a deactivation of the RABS II. To check this indicator, first go to Red BRAKE Warning Indicator Self Check. Allow the key to spring back from the START position to the RUN position. The yellow ABS warning indicator should perform a self check by illuminating for approximately two seconds and then turning off. If it turns back on and does not flash, then a system concern has been detected. Refer to Diagnostic Trouble Codes, Retrieving to obtain diagnostic trouble codes. If yellow ABS indicator fails to illuminate, go to Symptom Chart. Diagnostic Trouble Codes (DTC), Retrieving CAUTION: Care must be taken to connect only the black/orange stripe wire to ground. Connecting the mating connector wire to ground will result in a blown fuse. NOTE: Verify the ignition switch is in the RUN position (engine does not need to be running). Next, locate the black RABS II diagnostic connector C208. The diagnostic connector C208 has

2 two mating halves, one of which has a BK/O wire connected to it. Disconnect the two halves. Attach one end of a jumper wire to the BK/O wire side of the diagnostic connector C208. Ground the opposite end of the jumper wire until the ABS light begins to flash. Grounding this wire will start the yellow ABS warning indicator flashing. If grounding this wire does not start the yellow ABS warning indicator flashing, go to Symptom Chart. The code consists of a number of short flashes and ends with a long flash. Count the short flashes and include the following long flash in the count to obtain the code number. For example, three short flashes followed by one long flash indicates Diagnostic Trouble Code 4. The code will continue to repeat itself until the key is turned off. It is recommended that the code be verified by reading it several times. This code will be used later for system repair instructions. It should be written down for future use. A Diagnostic Trouble Code 16 is obtained when the anti-lock brake control module detects normal system operation. Diagnostic Trouble Codes, Erasing The last step of the system pre-check always includes clearing the keep-alive memory (KAM). Turn off the ignition while the diagnostic connector C208 halves are separated as described in the procedures for retrieving the diagnostic trouble code. The diagnostic connector C208 must be re-assembled to provide KAM power to the anti-lock brake control module. If a valid code has been obtained, go to the appropriate pinpoint test for that code, otherwise go to the Symptom Chart section below. Symptom Chart NOTE: Code 16 is always present, unless a system concern has been detected and a DTC has been stored. This code should be used by the technician to verify that the RAB system is OK. Code 16 will be output by the RABS module when the technician grounds circuit 571 (BK/O), or the RABS keep-alive memory fuse has blown. Please note that both the red BRAKE warning indicator self-check and test drive are required prior to performing the tests in this section. Failure to perform these procedures will greatly diminish the effectiveness of the diagnosis. Symptom Chart Condition Possible Sources Action The Red BRAKE Warning Indicator Does t Self-Check The Red BRAKE Warning Indicator Stays On When the Ignition Switch Is in RUN The Yellow ABS Warning Indicator Does t Self-Check The Yellow ABS Warning Indicator Self- Checks OK but Automatically Begins Flashing The Yellow ABS Warning Indicator Self- Checks OK, but Diagnostic Trouble Codes Are Retrieved When the Diagnostics Are Started DTC 2 Open RABS II Isolation Solenoid Circuit DTC 3 Open RABS II Dump Solenoid Circuit DTC 4 Open/Grounded RABS Valve Reset Circuit DTC 6 Erratic Rear Anti-Lock Brake Sensor Circuit DTC 7 Isolation Solenoid During Self- Check Red BRAKE warning indicator bulb. Fuse. Circuitry. Resistor/diode element. Unseated brake fluid level warning switch connector C149. Defective ignition prove-out switch. Circuitry. Damaged parking brake switch. Fuse. Circuitry. Yellow ABS warning indicator. Harness connector not fully seated with anti-lock brake control module. Anti-lock brake control module. Incorrect anti-lock brake control module type (RABS I instead of RABS II). Anti-lock brake control module. Circuitry. Keep-alive memory (KAM) Fuse 11. Circuitry. Incorrect anti-lock brake control module type (RABS I instead of RABS II). Anti-lock brake control module. Anti-lock brake control module or RABS valve connectors not fully seated. Terminal backout in the anti-lock brake control module and/or RABS valve harness connector. Bulkhead connector (between engine compartment and instrument panel) terminal backout or loose connection. Circuitry. RABS valve. Anti-lock brake control module. Anti-lock brake control module or RABS valve connectors not fully seated. Terminal backout in the anti-lock brake control module and/or RABS valve harness connector. Bulkhead connector (between engine compartment and instrument panel) terminal backout or loose connection. Circuitry. RABS valve. Anti-lock brake control module. Anti-lock brake control module or RABS valve connectors not fully seated. Terminal backout in the anti-lock brake control module and/or RABS valve harness connector. Bulkhead connector (between engine compartment and instrument panel) terminal backout or loose connection. Circuitry. RABS valve. Anti-lock brake control module. Anti-lock brake control module or RABS sensor connectors not fully seated. Terminal backout in the anti-lock brake control module connector. Bulkhead connector (between engine compartment and instrument panel) terminal backout or loose connection. Circuitry. RABS sensor. Damaged rear brake anti-lock sensor ring. Circuitry. RABS valve. Anti-lock brake control module. GO to Pinpoint Test A. GO to Pinpoint Test B. GO to Pinpoint Test C. GO to Pinpoint Test D. GO to Pinpoint Test E. GO to Pinpoint Test F. GO to Pinpoint Test G. GO to Pinpoint Test H. GO to Pinpoint Test J. GO to Pinpoint Test K. DTC 8 Dump Solenoid During Self- Circuitry. GO to Pinpoint Test L.

3 Check DTC 9 High Speed Sensor Resistance DTC 10 Low Speed Sensor Resistance DTC 11 Brake Pedal Position (BPP) Switch Always Closed DTC 12 Loss of Hydraulic Brake Fluid When ABS Is Activated Bulkhead connector between engine compartment and instrument panel terminals shorted. RABS valve. Anti-lock brake control module. Terminal backout in the anti-lock brake control module connector. Anti-lock brake control module or RABS sensor connectors not fully seated. Circuitry. Rear anti-lock brake sensor. Anti-lock brake control module. Circuitry. Rear anti-lock brake sensor. Anti-lock brake control module. Terminal backout in the anti-lock brake control module harness connector. Stoplamps. Circuitry. Brake pedal position (BPP) switch. Anti-lock brake control module. Low master cylinder fill level. Fluid leaks in vehicle brake system. Worn or damaged brake fluid level warning switch. Master cylinder float that sticks in the bottom of brake master cylinder reservoir (2K478) or does not float. Diode/resistor element. Damaged ignition switch. Circuitry. Damaged anti-lock brake control module. GO to Pinpoint Test M. GO to Pinpoint Test N. GO to Pinpoint Test P. GO to Pinpoint Test Q. DTC 13 RABS II Module Failure Anti-lock brake control module. GO to Pinpoint Test R. DTC 16 RAB System OK system faults detected. STOP. Rear anti-lock brake system functioning properly. Intermittent Problem Suspected Intermittent connections at speed sensor, RABS valve, anti-lock brake control module. Circuitry. Anti-lock brake control module. GO to Pinpoint Test S. Unwarranted RABS Activity Metal chips on rear anti-lock brake sensor pole piece. GO to Pinpoint Test J. Intermittent open rear anti-lock brake sensor circuit at intermediate connections especially bulkhead. Circuitry. Rear brake adjustment too tight. Brake linings are grabby. GO to Pinpoint Test S. INSPECT wiring harness from rear axle assembly to frame side rail for chafing or rub marks. ADJUST as necessary. REPAIR and/or REPLACE as necessary. One or Both Wheels Lock Up Damaged RABS valve reset switch. GO to Pinpoint Test H. Hydraulically inoperative RABS valve. GO to Pinpoint Test H. RABS sensor air gap too large. GO to Pinpoint Test J. RABS sensor/rear anti-lock brake sensor indicator does not produce sufficient output. Brake related concern: damp or contaminated rear brake shoe linings, stuck/leaking rear wheel cylinder or overadjusted rear brake drums. REFER to Pinpoint Test J. REPAIR and/or REPLACE as necessary. Hung-up parking brake. REFER to Section Brake pedal position switch input to anti-lock brake control module not present. GO to Pinpoint Test P. Stoplamps inoperative. REFER to Section Soft/Hard Brake Pedal Leaky dump valve (soft pedal). GO to Pinpoint Test H. Lack of Deceleration During Medium/Hard Brake Applications Leaky isolation valve during RABS stop (soft pedal). GO to Pinpoint Test K. Stoplight switch always on while driving. GO to Pinpoint Test P. Hydraulic leak in rear brake tube or rear brake hose, fitting, brake master cylinder, rear wheel cylinder, or front disc brake caliper. Air in brake system. Brake related concern: little or no vacuum boost, stuck or inoperative rear wheel cylinder or front disc brake caliper, or pinched or crimped rear brake tube or rear brake hose. REPAIR as necessary. BLEED the system. REFER to Section REPAIR as necessary. Leaky dump valve. GO to Pinpoint Test H. Stuck shut isolation valve. GO to Pinpoint Test H. Circuitry. GO to Pinpoint Test J. Metal chips on rear anti-lock brake sensor. GO to Pinpoint Test J. Borderline high rear anti-lock brake sensor to rear anti-lock brake sensor indicator air gap, excessive rear anti-lock brake sensor indicator radial runout, damaged or missing rear anti-lock brake sensor indicator teeth. Hydraulic leak in brake line tubing or rear brake hose, fitting, brake master cylinder, rear wheel cylinder, or front disc brake caliper. Air in brake system. Brake related concern: little or no vacuum boost, stuck or inoperative wheel cylinder or caliper, pinched or crimped rear brake hose or brake line tubing, or ineffective brake shoe or pad linings. GO to Pinpoint Test J. REPAIR as necessary. BLEED the system. REFER to Section REPAIR as necessary.

4 Pinpoint Tests PINPOINT TEST A: THE RED BRAKE WARNING INDICATOR DOES NOT SELF-CHECK A1 CHECK THE RED BRAKE WARNING INDICATOR/FUSE Engage the parking brake. Does the red BRAKE warning indicator illuminate? A2 CHECK THE DIODE RESISTOR ELEMENT AND CIRCUIT 531 (DG/Y) RELEASE the parking brake. GO to A2. REFER to Section A. Brake Fluid Level Warning Switch C149 Connect a jumper wire between brake fluid level warning switch C149-3, circuit 531 (DG/Y), and ground. Does the red BRAKE warning indicator illuminate? A3 CHECK THE BRAKE FLUID LEVEL WARNING SWITCH GO to A3. REPAIR circuit 531 (DG/Y) and/or diode resistor element. REPEAT the system pre-check. NOTE: Check for corroded or unseated pins before repairing and/or replacing the brake fluid level warning switch. Connect a jumper wire between brake fluid level warning switch C149-3, circuit 531 (DG/Y), and brake fluid level warning switch C149-2, circuit 512 (T/LG).

5 Does the red BRAKE warning indicator lamp illuminate? REPLACE the brake fluid level warning switch. REPEAT the system pre-check. A4 CHECK CIRCUIT 512 (T/LG) FOR AN OPEN GO to A4. Anti-Lock Brake Control Module C217 Measure the resistance between anti-lock brake control module C217-2, circuit 512 (T/LG), and brake fluid level warning switch C149-2, circuit 512 (T/LG). Is the resistance less than 5 ohms? GO to A5. A5 CHECK THE IGNITION SWITCH REPAIR circuit 512 (T/LG). REPEAT the system pre-check. Ignition Switch C240 Measure the resistance between ignition switch terminal P1, and ground, while in the START position. Is the resistance less than 5 ohms? GO to A6. A6 CHECK CIRCUIT 531 (DG/Y) FOR AN OPEN REPLACE the ignition switch. REPEAT the system pre-check. Measure the resistance between brake warning switch C149-3, circuit 531 (DG/Y), and ignition switch C240-P1, circuit 531 (DG/Y).

6 Is the resistance less than 5 ohms? REPLACE the anti-lock brake control module. REPEAT system pre-check. REPAIR circuit 531 (DG/Y). REPEAT the system pre-check. PINPOINT TEST B: THE RED BRAKE WARNING INDICATOR STAYS ON WHEN THE IGNITION SWITCH IS IN RUN B1 CHECK THE WARNING INDICATOR LAMPS Disengage the parking brake. Do both the red BRAKE warning indicator and the yellow ABS warning indicator illuminate? RETRIEVE the codes. GO to Symptom Chart. B2 CHECK THE PARKING BRAKE SWITCH GO to B2. Parking Brake Switch C243 Does the red BRAKE warning indicator illuminate? GO to B3. B3 CHECK THE ANTI-LOCK BRAKE CONTROL MODULE REPLACE the parking brake switch. REPEAT the system pre-check.

7 Anti-Lock Brake Control Module C217 Does the red BRAKE warning indicator illuminate? REFER to Section A. REPLACE the anti-lock brake control module. REPEAT the system pre-check. PINPOINT TEST C: THE YELLOW ABS WARNING INDICATOR DOES NOT SELF-CHECK C1 CHECK THE FUSE JUNCTION PANEL FUSE 2 (15A) Fuse Junction Panel Fuse 2 (15A) Is the fuse OK? C2 CHECK ANTI-LOCK BRAKE CONTROL MODULE GROUND GO to C2. REPLACE the failed fuse. TEST the system for normal operation. If the fuse fails again, CHECK for short to ground. REPAIR as necessary. REPEAT the system pre-check. NOTE: When checking resistance in the RABS system, always disconnect the battery to starter relay cable. Improper resistance can occur with the vehicle battery connected. Anti-Lock Brake Control Module C217 Disconnect the battery ground cable. On vehicles equipped with dual batteries, refer to Section Measure the resistance between anti-lock brake control module C217-4, circuit 530 (LG/Y), and ground. Is the resistance less than 5 ohms? RECONNECT the battery ground cable. On vehicles equipped with dual batteries, refer to Section GO to C3.

8 C3 CHECK VOLTAGE TO THE YELLOW ABS WARNING INDICATOR REPAIR circuit 530 (LG/Y). REPEAT the system pre-check. Measure the voltage between anti-lock brake control module C217-7, circuit 603 (DG), and ground. Is the voltage greater than 10 volts? REPLACE the anti-lock brake control module. REPEAT the system pre-check. C4 CHECK CIRCUIT 603 (DG) FOR AN OPEN GO to C4. Instrument Cluster C225 Measure the resistance between anti-lock brake control module C217-7, circuit 603 (DG), and instrument cluster C225-8, circuit 603 (DG). Is the resistance less than 5 ohms? REPAIR and/or REPLACE the instrument cluster. REPEAT the system pre-check. REPAIR circuit 603 (DG). REPEAT the system pre-check. PINPOINT TEST D: THE YELLOW ABS WARNING INDICATOR SELF-CHECKS OK BUT AUTOMATICALLY BEGINS FLASHING D1 OBSERVE THE YELLOW ABS WARNING INDICATOR LAMP FOR FLASH SEQUENCE NOTE: A diagnostic trouble code (DTC) will appear as one or more short pulses followed by one long pulse. Observe the yellow ABS warning indicator lamp. Is the flash sequence a DTC? GO to the Symptom Chart for diagnosis of the DTC.

9 D2 CHECK FUSE JUNCTION PANEL FUSE 11 (15A) GO to D2. Fuse Junction Panel Fuse 11 (15A) Is the fuse OK? GO to D3. D3 CHECK VOLTAGE TO THE ANTI-LOCK BRAKE CONTROL MODULE REPLACE the failed fuse. TEST the system for normal operation. If the fuse fails again, CHECK for short to ground. REPAIR as necessary. REPEAT the system pre-check. Anti-Lock Brake Control Module C217 Measure the voltage between anti-lock brake control module C217-1, circuit 601 (LB/PK), and ground; and between anti-lock brake control module C217-9, circuit 601 (LB/PK), and ground, while shaking the wiring harness. Is the voltage steady and greater than 10 volts? GO to D4. D4 CHECK THE ANTI-LOCK BRAKE CONTROL MODULE GROUND REPAIR circuit 601 (LB/PK). REPEAT the system pre-check. Disconnect the battery ground cable. On vehicles equipped with dual batteries, refer to Section Measure the resistance between anti-lock brake control module C217-4, circuit 530 (LG/Y), and ground, while shaking the wiring harness.

10 Is the resistance steady and less than 5 ohms? REPLACE the anti-lock brake control module. REPEAT the system pre-check. REPAIR circuit 530 (LG/Y). REPEAT the system pre-check. PINPOINT TEST E: THE YELLOW ABS WARNING INDICATOR SELF CHECKS OK BUT NO DIAGNOSTIC TROUBLE CODES ARE RETRIEVED WHEN THE DIAGNOSTICS ARE STARTED E1 CHECK THE BRAKE PEDAL POSITION (BPP) SWITCH Depress the brake pedal (2455). Do the stoplamps function properly? GO to E2. REFER to Section E2 CHECK THE BRAKE PEDAL POSITION (BPP) SWITCH INPUT TO THE ANTI-LOCK BRAKE CONTROL MODULE Anti-Lock Brake Control Module C217 Depress the brake pedal.

11 Measure the voltage between anti-lock brake control module C217-11, circuit 511 (LG), and ground. Is the voltage greater than 10 volts? GO to E3. E3 CHECK VOLTAGE TO THE ANTI-LOCK BRAKE CONTROL MODULE REPAIR circuit 511 (LG). REPEAT the system pre-check. Measure the voltage between anti-lock brake control module C217-1, circuit 601 (LB/PK), and ground; and between anti-lock brake control module C217-9, circuit 601 (LB/PK), and ground. Are the voltages greater than 10 volts? E4 CHECK CIRCUIT 603 (DG) FOR A SHORT TO GROUND GO to E4. REPAIR circuit 601 (LB/PK). REPEAT the system pre-check. Observe the yellow ABS warning indicator. Is the yellow ABS warning indicator on continuously? REPAIR circuit 603 (DG). REPEAT the system pre-check. GO to E5. E5 CHECK THE KEEP-ALIVE MEMORY (KAM) CIRCUIT 571 (BK/O)

12 Measure the resistance between anti-lock brake control module C217-12, circuit 571 (BK/O), and diagnostic test connector C208M, circuit 571 (BK/O). Is the resistance less than 5 ohms? REPLACE the anti-lock brake control module. REPEAT the system pre-check. REPAIR circuit 571 (BK/O). REPEAT the system pre-check. PINPOINT TEST F: DIAGNOSTIC TROUBLE CODE (DTC) 2 OPEN RABS II ISOLATION SOLENOID CIRCUIT F1 DETERMINE IF THE FAULT IS HARD OR INTERMITTENT Does the yellow ABS warning indicator illuminate? GO to F2. F2 CHECK CIRCUIT 599 (PK/LG) FOR AN OPEN Intermittent fault. GO to Pinpoint Test S. RABS Valve C153 Anti-Lock Brake Control Module C217 Measure the resistance between anti-lock brake control module C217-13, circuit 599 (PK/LG), and RABS valve C153-4, circuit 599 (PK/LG).

13 Is the resistance less than 5 ohms? GO to F3. F3 CHECK THE RESISTANCE OF THE RABS VALVE ISOLATION SOLENOID REPAIR circuit 599 (PK/LG). REPEAT the system pre-check. Measure the resistance between the RABS valve terminals 3 and 4. Is the resistance between 2.7 and 6.6 ohms? REPLACE the anti-lock brake control module. REPEAT the system pre-check. REPLACE the RABS valve. REPEAT the system pre-check. PINPOINT TEST G: DIAGNOSTIC TROUBLE CODE (DTC) 3 OPEN RABS II DUMP SOLENOID CIRCUIT G1 DETERMINE IF THE FAULT IS HARD OR INTERMITTENT Does the yellow ABS warning indicator lamp illuminate?

14 Hard fault. GO to G2. G2 CHECK CIRCUIT 664 (Y/LG) FOR AN OPEN Intermittent fault. GO to Pinpoint Test S. RABS Valve C153 Anti-Lock Brake Control Module C217 Measure the resistance between anti-lock brake control module C217-14, circuit 664 (Y/LG), and RABS valve C153-1, circuit 664 (Y/LG); and between anti-lock brake control module C217-8, circuit 664 (Y/LG), and RABS valve C153-1, circuit 664 (Y/LG). Are the resistances less than 5 ohms? GO to G3. G3 CHECK THE RESISTANCE OF THE RABS DUMP VALVE SOLENOID REPAIR circuit 664 (Y/LG). REPEAT the system pre-check. Measure the resistance between the RABS valve terminals 1 and 3. Is resistance between 0.9 and 3.3 ohms? REPLACE the anti-lock brake control module. REPEAT the system pre-check. REPLACE the RABS valve. REPEAT the system pre-check. PINPOINT TEST H: DIAGNOSTIC TROUBLE CODE (DTC) 4 OPEN/GROUNDED RABS VALVE RESET CIRCUIT H1 DETERMINE IF THE FAULT IS HARD OR INTERMITTENT

15 Do the yellow ABS and red BRAKE warning indicators illuminate? GO to H2. H2 CHECK CIRCUIT 535 (LB/R) FOR AN OPEN Intermittent fault. GO to Pinpoint Test S. RABS Valve C153 Anti-Lock Brake Control Module C217 Measure the resistance between anti-lock brake control module C217-6, circuit 535 (LB/R), and RABS valve C153-2, circuit 535 (LB/R). Is the resistance less than 5 ohms? GO to H3. H3 CHECK CIRCUIT 57 (BK) FOR AN OPEN REPAIR circuit 535 (LB/R). REPEAT the system pre-check. Measure the resistance between RABS valve C153-3, circuit 57 (BK), and ground.

16 Is the resistance less than 5 ohms? H4 CHECK CIRCUIT 535 (LB/R) FOR A SHORT TO GROUND GO to H4. REPAIR circuit 57 (BK). REPEAT the system pre-check. Measure the resistance between anti-lock brake control module C217-6, circuit 535 (LB/R), and ground. Is the resistance greater than 10,000 ohms? GO to H5. H5 CHECK THE RABS VALVE RESET SWITCH REPAIR circuit 535 (LB/R). REPEAT the system pre-check. Measure the resistance between RABS valve terminal 2 and ground. Is the resistance greater than 10,000 ohms?

17 REPLACE the anti-lock brake control module. REPEAT the system pre-check. REPLACE the RABS valve. REPEAT the system pre-check. PINPOINT TEST J: DIAGNOSTIC TROUBLE CODE (DTC) 6 ERRATIC REAR ANTI-LOCK BRAKE SENSOR CIRCUIT J1 DETERMINE IF THE FAULT IS HARD OR INTERMITTENT Does the yellow ABS warning indicator illuminate? GO to J2. J2 VERIFY INTEGRITY OF REAR ANTI-LOCK BRAKE SENSOR WIRE ROUTING Intermittent fault. GO to Pinpoint Test S. Inspect the wire routing. Are the wires secure, undamaged, and properly routed? GO to J3. J3 CHECK THE REAR ANTI-LOCK BRAKE SENSOR RESISTANCE REPAIR as necessary. REPEAT the system pre-check. Anti-Lock Brake Control Module C217 Measure the resistance between anti-lock brake control module C217-3, circuit 519 (LG/BK), and anti-lock brake control module C217-10, circuit 523 (R/PK), while shaking the wire harness. Is the resistance steady and between ohms? GO to J4. GO to J8. J4 CHECK THE REAR ANTI-LOCK BRAKE SENSOR CIRCUIT FOR A SHORT TO GROUND Measure the resistance between anti-lock brake control module C217-3, circuit 519 (LG/BK), and ground; and between anti-lock brake control module C217-10, circuit 523 (R/PK), and ground.

18 Are the resistances greater than 10,000 ohms? GO to J5. GO to J10. J5 CHECK FOR METAL SHAVINGS ON THE REAR ANTI-LOCK BRAKE SENSOR MAGNET POLE Remove the rear anti-lock brake sensor from the rear differential case (4204) and inspect for metal shavings and chips on the rear anti-lock brake sensor pole piece. Are metal shavings/chips present? DRAIN and CLEAN the rear differential case. GO to J6. J6 CHECK REAR ANTI-LOCK BRAKE SENSOR OUTPUT GO to J7. Anti-Lock Brake Control Module C217 Raise and support the vehicle on a hoist so that all wheels are clear of the ground. Turn the wheels at 8 km/h (5 mph). Measure the voltage between anti-lock brake control module C217-3, circuit 519 (LG/BK), and anti-lock brake control module C217-10, circuit 523 (R/PK).

19 Is the voltage steady and approximately 650 milli-vac RMS? J7 CHECK THE REAR ANTI-LOCK BRAKE SENSOR RING TEETH GO to J7. REPLACE the rear anti-lock brake sensor. REPEAT the system pre-check. Remove the differential case cover. Carefully inspect each tooth on the rear anti-lock brake sensor indicator. Are any teeth missing or damaged? J8 CHECK THE REAR ANTI-LOCK BRAKE SENSOR FOR AN OPEN REPLACE the rear anti-lock brake sensor indicator. REPEAT the system pre-check. REPLACE the anti-lock brake control module. REPEAT the system pre-check. Rear Anti-Lock Brake Sensor C415 Measure the resistance between the rear anti-lock brake sensor terminals. Is the resistance between 800 and 3500 ohms? GO to J9. J9 CHECK CIRCUIT 519 (LG/BK) FOR AN OPEN REPLACE the rear anti-lock brake sensor. REPEAT the system pre-check. Measure the resistance between anti-lock brake control module C217-3, circuit 519 (LG/BK), and rear anti-lock

20 brake sensor C415, circuit 519 (LG/BK). Is the resistance less than 5 ohms? J10 CHECK THE REAR ANTI-LOCK BRAKE SENSOR FOR SHORT TO GROUND REPAIR circuit 523 (R/PK). REPEAT the system pre-check. REPAIR circuit 519 (LG/BK). REPEAT the system pre-check. Rear Anti-Lock Brake Sensor C415 Measure the resistance between the rear anti-lock brake sensor terminal, and ground. Is the resistance greater than 10,000 ohms? J11 CHECK CIRCUIT 519 (LG/BK) FOR SHORT TO GROUND GO to J11. REPLACE the rear anti-lock brake sensor. REPEAT the system pre-check. Measure the resistance between anti-lock brake control module C217-3, circuit 519 (LG/BK), and ground. Is the resistance greater than 10,000 ohms? REPAIR circuit 523 (R/PK). REPEAT the system pre-check. REPAIR circuit 519 (LG/BK). REPEAT the system pre-check. PINPOINT TEST K: DIAGNOSTIC TROUBLE CODE (DTC) 7 NO ISOLATION SOLENOID DURING SELF-CHECK K1 DETERMINE IF THE FAULT IS HARD OR INTERMITTENT

21 Does the yellow ABS warning indicator lamp illuminate? GO to K2. K2 CHECK RABS ISOLATION VALVE Intermittent fault. GO to Pinpoint Test S. Brake Pressure Regulator Valve C153 Check the resistance between C153, component side, circuit 599 (PK/LG) and C153, component side, circuit 57 (BK). Is the resistance between 3 and 6 ohms? GO to K3. K3 CHECK CIRCUIT 599 (PK/LG) FOR AN OPEN INSTALL a new brake pressure regulator valve. REPEAT the system pre-check. Check the resistance between C217, pin 13, circuit 599 (PK/LG), and C153, circuit 599 (PK/LG). Is the resistance less than 5 ohms? GO to K4. K4 CHECK CIRCUIT 57 (BK) FOR AN OPEN REPAIR circuit 599 (PK/LG). REPEAT the system pre-check. Check the resistance between C153, circuit 57 (BK) and ground. Is the resistance less than 5 ohms?

22 INSTALL a new RABS valve. REPEAT the system pre-check. REPAIR circuit 57 (BK). REPEAT the system pre-check. PINPOINT TEST L: DIAGNOSTIC TROUBLE CODE 8 NO DUMP SOLENOID DURING SELF-CHECK L1 DETERMINE IF THE FAULT IS HARD OR INTERMITTENT Does the yellow ABS warning indicator illuminate? Hard fault. GO to L2. Intermittent fault. GO to Pinpoint Test S. L2 CHECK CIRCUIT 664 (Y/LG) AND RABS DUMP VALVE SOLENOID FOR SHORT TO GROUND Anti-Lock Brake Control Module C217 Measure the resistance between anti-lock brake control module C217-8, circuit 664 (Y/LG), and anti-lock brake control module circuit 664 (Y/LG), and ground. Are the resistances between 1-3 ohms? REPLACE the anti-lock brake control module. REPEAT the system pre-check. GO to L3.

23 L3 CHECK THE RABS VALVE DUMP SOLENOID RABS Valve C153 Measure the resistance between the RABS valve terminals 1 and 3. Is the resistance 3-6 ohms? REPAIR circuit 664 (Y/LG). REPEAT the system pre-check. REPLACE the RABS valve. REPEAT the system pre-check. PINPOINT TEST M: DIAGNOSTIC TROUBLE CODE (DTC) 9 HIGH SPEED SENSOR RESISTANCE M1 DETERMINE IF THE FAULT IS HARD OR INTERMITTENT Does the yellow ABS warning indicator illuminate? GO to M2. Intermittent fault. GO to Pinpoint Test S. M2 VERIFY THE INTEGRITY OF THE REAR ANTI-LOCK BRAKE SENSOR WIRE ROUTING Inspect the wire routing. Are the wires secure, undamaged, and properly routed? GO to M3. M3 CHECK THE REAR ANTI-LOCK BRAKE SENSOR RESISTANCE REPAIR as necessary. REPEAT the system pre-check. Anti-Lock Brake Control Module C217 Measure the resistance between anti-lock brake control module C217-3, circuit 519 (LG/BK), and anti-lock brake

24 control module C217-10, circuit 523 (R/PK), while shaking the wire harness. Is the resistance steady and between ohms? GO to M4. GO to M5. M4 CHECK THE REAR ANTI-LOCK BRAKE SENSOR CIRCUIT FOR A SHORT TO GROUND Measure the resistance between anti-lock brake control module C217-3, circuit 519 (LG/BK), and ground; and between anti-lock brake control module C217-10, circuit 523 (R/PK), and ground. Are the resistances greater than 10,000 ohms? REPLACE the anti-lock brake control module. REPEAT the system pre-check. GO to M7. M5 CHECK THE REAR ANTI-LOCK BRAKE SENSOR FOR AN OPEN Rear Anti-Lock Brake Sensor C415 Measure the resistance between the rear anti-lock brake control sensor terminals. Is the resistance between 800 and 3500 ohms? GO to M6. M6 CHECK CIRCUIT 519 (LG/BK) FOR AN OPEN REPLACE the anti-lock brake sensor. REPEAT the system pre-check. Measure the resistance between anti-lock brake control module C217-3, circuit 519 (LG/BK), and rear anti-lock

25 brake sensor C415, circuit 519 (LG/BK). Is the resistance less than 5 ohms? M7 CHECK THE REAR ANTI-LOCK BRAKE SENSOR FOR SHORT TO GROUND REPAIR circuit 523 (R/PK). REPEAT the system pre-check. REPAIR circuit 519 (LG/BK). REPEAT the system pre-check. Rear Anti-Lock Brake Sensor C415 Measure the resistance between the rear anti-lock brake sensor terminal, and ground. Is the resistance greater than 10,000 ohms? M8 CHECK CIRCUIT 519 (LG/BK) FOR SHORT TO GROUND GO to M8. REPLACE the rear anti-lock brake sensor. REPEAT the system pre-check. Measure the resistance between the anti-lock brake control module C217-3, circuit 519 (LG/BK), and ground. Is the resistance greater than 10,000 ohms? REPAIR circuit 523 (R/PK). REPEAT the system pre-check. REPAIR circuit 519 (LG/BK). REPEAT the system pre-check. PINPOINT TEST N: DIAGNOSTIC TROUBLE CODE (DTC) 10 LOW SPEED SENSOR RESISTANCE N1 DETERMINE IF THE FAULT IS HARD OR INTERMITTENT

26 Does the yellow ABS warning indicator illuminate? GO to N2. N2 CHECK CIRCUITS 519 (LG/BK) AND 523 (R/PK) FOR A SHORT Intermittent fault. GO to Pinpoint Test S. Rear Anti-Lock Brake Sensor C415 Anti-Lock Brake Control Module C217 Measure the resistance between anti-lock brake control module C217-3, circuit 519 (LG/BK), and anti-lock brake control module circuit 523 (R/PK). Is the resistance greater than 10,000 ohms? GO to N3. N3 CHECK CIRCUITS 523 (R/PK) AND 519 (LG/BK) FOR SHORT TO GROUND REPAIR the short between circuits 519 (LG/PK) and 523 (R/PK). REPEAT the system pre-check. Measure the resistance between anti-lock brake control module C217-3, circuit 519 (LG/BK), and ground; and between anti-lock brake control module C217-10, circuit 523 (R/PK), and ground. Are the resistances greater than 10,000 ohms?

27 GO to N4. N4 CHECK THE REAR ANTI-LOCK BRAKE SENSOR RESISTANCE REPAIR circuit 523 (R/PK) and/or 519 (LG/BK). REPEAT the system pre-check. Measure the resistance between the rear anti-lock brake sensor terminals. Is the resistance between ohms? GO to N5. N5 CHECK THE REAR ANTI-LOCK BRAKE SENSOR FOR A SHORT TO GROUND REPLACE the rear anti-lock brake sensor. REPEAT the system pre-check. Measure the resistance between rear anti-lock brake sensor terminal, and ground. Is the resistance greater than 10,000 ohms? REPLACE the rear anti-lock brake sensor. REPEAT the system pre-check. REPLACE the anti-lock brake control module. REPEAT the system pre-check. PINPOINT TEST P: DIAGNOSTIC TROUBLE CODE (DTC) 11 BRAKE PEDAL POSITION (BPP) SWITCH ALWAYS CLOSED P1 CHECK STOPLAMP OPERATION Depress the brake pedal. Observe the stoplamps. Do the stoplamps function correctly? GO to P2. P2 CHECK CIRCUIT 511 (LG) FOR AN OPEN REFER to Section

28 Anti-Lock Brake Control Module C217 Depress the brake pedal. Measure the voltage between anti-lock brake control module C217-11, circuit 511 (LG), and ground. Is the voltage greater than 10 volts? REPLACE the anti-lock brake control module. REPEAT the system pre-check. REPAIR circuit 511 (LG). REPEAT the system pre-check. PINPOINT TEST Q: DIAGNOSTIC TROUBLE CODE (DTC) 12 LOSS OF HYDRAULIC BRAKE FLUID WHEN ABS IS ACTIVATED Q1 DETERMINE IF THE FAULT IS HARD OR INTERMITTENT Does the yellow ABS warning indicator illuminate? GO to Q2. Q2 CHECK THE BRAKE FLUID LEVEL Intermittent fault. GO to Pinpoint Test S. Check the brake fluid level in the brake master cylinder reservoir. Is the fluid level OK? GO to Q3.

29 Q3 CHECK CIRCUIT 531 (DG/Y) FOR SHORT TO GROUND CHECK for leaks in the brake system. REPAIR as necessary. FILL the brake master cylinder reservoir to the specified level. REPEAT the system pre-check. Brake Fluid Level Switch C149 Measure the resistance between brake fluid level switch C149-3, circuit 531 (DG/Y), and ground. Is the resistance greater than 10,000 ohms? GO to Q4. Q4 CHECK THE DIODE/RESISTOR ELEMENT GO to Q6. Engage the parking brake. Measure the resistance between brake fluid level switch C149-3, circuit 531 (DG/Y), and ground. Is the resistance greater than 10,000 ohms? GO to Q5. Q5 CHECK CIRCUIT 512 (T/LG) FOR SHORT TO GROUND REPLACE the resistor/diode element. REPEAT the system pre-check. Anti-Lock Brake Control Module C217 Measure the resistance between brake fluid level switch C149-2, circuit 512 (T/LG), and ground.

30 Is the resistance greater than 10,000 ohms? RECONNECT the brake fluid level switch. GO to Q7. Q6 CHECK THE IGNITION SWITCH REPAIR circuit 512 (T/LG). REPEAT the system pre-check. Ignition Switch C240 Measure the resistance between brake fluid level switch C149-3, circuit 531 (DG/Y), and ground. Is the resistance greater than 10,000 ohms? REPLACE the ignition switch. REPEAT the system pre-check. Q7 CHECK THE BRAKE FLUID LEVEL SWITCH REPAIR circuit 531 (DG/Y). REPEAT the system pre-check. Measure the resistance between anti-lock brake control module C217-2, circuit 512 (T/LG), and ground. Is the resistance 5 ohms or less? REPLACE the brake fluid level switch. REPEAT the system pre-check. REPLACE the anti-lock brake control module. REPEAT the system pre-check. PINPOINT TEST R: DIAGNOSTIC TROUBLE CODE (DTC) 13 RABS II MODULE FAILURE R1 CHECK THE KEEP-ALIVE MEMORY (KAM) FUSE Observe the yellow ABS warning indicator proveout. Does the yellow ABS warning indicator prove out normally?

31 R2 CHECK LOW SPEED ABS STOP GO to R2. NOTE: Wetting down the area where the stop is to be performed will aid in the accomplishment of this test. REPLACE the KAM fuse junction panel fuse 11 (15A). If the fuse fails again, CHECK for short to ground. REPAIR as necessary. REPEAT the system pre-check. Drive at approximately 16 km/h (10 mph). Press on the brake pedal hard enough to lock all four wheels, and observe the rear wheels in mirrors or using an observer. Do one or both of the wheels lock up consistently? (Momentary lockup is permissible.) GO to R3. If other symptoms are detected, GO to Symptom Chart. If the yellow ABS warning indicator does not illuminate, GO to R4. R3 CHECK FOR UNWARRANTED ABS ACTIVITY NOTE: Stopping must be performed on dry pavement. NOTE: Windshield wipers must be turned off during this test. If the yellow ABS warning indicator illuminates and stays illuminated, REPEAT the system pre-check. Drive at approximately km/h (20 mph). Perform a normal traffic stop. Feel for pulsation in the brake pedal during the stop and within 10 seconds after the vehicle has come to a stop. Is there any pulsation in the brake pedal at any time during the stop or within 10 seconds after the vehicle has stopped? GO to Symptom Chart. If the other symptoms are detected, GO to Symptom Chart. If the yellow ABS warning indicator does not illuminate, GO to R4. R4 CHECK THE BRAKE PEDAL POSITION (BPP) SWITCH If the yellow ABS warning indicator illuminates and stays illuminated, REPEAT the system pre-check. Depress the brake pedal. Do the stoplamps function properly? REPEAT the system pre-check. GO to Pinpoint Test P. PINPOINT TEST S: INTERMITTENT PROBLEM DIAGNOSIS

32 S1 CLEAR THE DTCs Reconnect the system. Clear all DTCs. Does the yellow ABS warning indicator prove out? S2 WIGGLE TEST GO to S3. GO to S2. NOTE: Start at one component and wiggle connector by connector until the whole circuit has been tested. Wiggle an affected circuit in one location only. Observe the yellow ABS warning indicator. Does the yellow ABS warning indicator illuminate? REPAIR the wire, terminal, or connector in question. GO to S3. S3 RETRIEVE CODES GO to S4. Retrieve the DTCs. Is a DTC retrieved? GO to Symptom Chart. GO to S4. S4 VERIFY THE CONDITION IS RESOLVED Clear all DTCs. Retrieve the DTCs. Is DTC 16 set? STOP. The repair is complete. REFER to Symptom Chart.