Page 1 of 8 HW7 DTC P1443: CHECK THE VOLTAGE ON THE PURGE FLOW (PF) SENSOR CIRCUIT VOLTAGE WITH ENGINE RUNNING Continuous Memory Diagnostic Trouble Code (DTC) P1443 indicates an incorrect evaporative system purge control valve flow. Obstructed, open or cracked hoses between EVAP canister purge valve and intake manifold. Damaged EVAP canister purge valve. Damaged PF sensor. Check for loose pins or broken wires by pulling moderately on the PF, VPWR and PWR GND circuits at PF sensor harness connector. Repair as necessary. Reconnect PF sensor. Connect scan tool. Key on, engine running. Did the EVAPPF PID fluctuate around 2.50 volts or 1.00 volt in one minute? For voltage from 2.20 to 2.60 volts: GO to HW18. For voltage from 0.90 to 1.10 volts: GO to HW8. GO to HW19. HW8 DTC P1443: VISUAL CHECK OF EVAPORATIVE EMISSION SYSTEM Continuous Memory Diagnostic Trouble Code (DTC) P1443 indicates an Evaporative emission control system or evaporative canister purge valve (mechanical) malfunction. Damaged EVAP canister. Pinched, plugged, blocked, cracked, cut or disconnected fuel vapor tubes/hoses between the fuel tank, EVAP canister, EVAP canister purge valve, purge flow (PF) sensor, and the engine intake manifold. Damaged EVAP canister purge valve. Damaged PF sensor. EVAP CANISTER PURGE, or PF circuit shorted to VPWR. te: Fuel saturation of EVAP canister cannot be effectively checked by the canister weight or intensity of odor (smell). Check for kinked or pinched fuel vapor tubes/hoses between EVAP canister, EVAP canister purge valve and engine intake manifold. Check for cracked or smashed EVAP canister. Is a fault indicated? For Escort/Tracer, Mustang, Thunderbird/Cougar, Ranger, Aerostar: REPAIR fuel vapor tubes/hoses as necessary. If EVAP canister is cracked or smashed, GO to Powertrain/Engine System Group, Evaporative Emission Section in the Workshop Manual. If components are replaced, GO to HW42. GO to HW11. All Other: GO to HW9. HW9 CHECK FOR VPWR VOLTAGE TO EVAP CANISTER PURGE VALVE Disconnect EVAP canister purge valve harness connector. Measure VPWR circuit voltage at EVAP canister purge valve harness connector to battery negative post. Was the voltage greater than 10.5 volts? GO to HW10. REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. HW10 CHECK FOR INTAKE MANIFOLD VACUUM AT THE EVAP CANISTER WHILE ELECTRICALLY CYCLING THE EVAP CANISTER PURGE VALVE Install breakout box, connect PCM to breakout box. Disconnect fuel vapor hose to EVAP canister purge valve at EVAP canister. Install a vacuum gauge to open end of fuel vapor hose. Start engine. Idle engine for 5 minutes.

Page 2 of 8 Observe the vacuum gauge. Reading must be near 0 kpa (0 in-hg). Connect a jumper between PCM test pin 56 and PCM test pin 51 or 103, while engine is still running. Idle the engine for additional 5 to 10 minutes. Observe the vacuum gauge. Did the vacuum reading change from near 0 kpa (0 in-hg) to 33.77 kpa (10 in-hg) or greater with addition of jumper? REMOVE vacuum gauge. LEAVE the fuel vapor hose from EVAP canister disconnected. REMOVE vacuum gauge. INSPECT the fuel vapor tubes/hoses between the EVAP canister and the EVAP canister purge valve and between the EVAP canister purge valve and the intake manifold for small cracks, splits or holes. REPAIR as necessary. RESTORE vehicle. GO to HW11. For vacuum readings within 20.26 kpa (6 in-hg)-33.77 kpa (10 in-hg): GO to HW12. For vacuum readings less than 20.26 kpa (6 in-hg): GO to HW13. HW11 CHECK EVAP CANISTER Disconnect fuel vapor hose to EVAP canister purge valve at EVAP canister. Check for contamination or blockages at all ports on EVAP canister (to the fuel tank, to the EVAP canister purge valve and to the atmosphere). Is a fault indicated? REPAIR EVAP canister. GO to Powertrain/Engine System Group, Evaporative Emission Section in the Workshop Manual. RESTORE vehicle. If components are replaced, GO to HW42. GO to HW12. HW12 CHECK FOR FUEL VAPOR HOSE LEAK BETWEEN EVAP CANISTER PURGE VALVE AND EVAP CANISTER Disconnect other end of fuel vapor hose from EVAP canister at EVAP canister purge valve. Plug open end of fuel vapor hose at EVAP canister. Install a hand vacuum pump to open end of fuel vapor hose at EVAP canister purge valve. Apply 53 kpa (16 in-hg) of vacuum with vacuum pump. Does the vacuum pump hold the vacuum? REMOVE plug in hose. GO to HW13. REPLACE damaged fuel vapor hose. RESTORE vehicle. GO to HW42. HW13 CHECK FOR FUEL VAPOR HOSE BLOCKAGE BETWEEN EVAP CANISTER PURGE VALVE AND EVAP CANISTER Disconnect other end of fuel vapor hose from EVAP canister at EVAP canister purge valve. Install a hand vacuum pump to open end of fuel vapor hose at EVAP canister purge valve. Apply 53 kpa (16 in-hg) of vacuum with vacuum pump. Does the vacuum pump hold the vacuum? REMOVE vacuum pump. For Escort/Tracer, Mustang, Thunderbird/Cougar, Ranger, Aerostar:: REMOVE vacuum pump. REPAIR or STRAIGHTEN fuel vapor hose as necessary. RESTORE vehicle. GO to HW42. RECONNECT fuel vapor hose at EVAP canister. LEAVE other end of fuel vapor hose disconnected at EVAP canister purge valve. GO to HW17. All Others: RECONNECT fuel vapor hose between EVAP canister and EVAP canister purge valve. GO to HW14. HW14 CHECK FOR FILTER CONTAMINATION OR DAMAGE TO THE EVAP CANISTER PURGE VALVE Disconnect vacuum line from input vacuum port to intake manifold on EVAP canister purge valve. (Refer to EVAP canister purge valve vacuum schematic at the beginning of this Pinpoint Test.) Install a hand vacuum pump to input vacuum port on EVAP canister purge valve. Apply 48-52 kpa (10-15 in-hg) of vacuum to EVAP canister purge valve. Does the EVAP canister purge valve hold vacuum or show a very slow release of vacuum to atmosphere? REPAIR EVAP canister purge valve filter blockage or REPLACE EVAP canister purge valve. RESTORE vehicle. GO to HW42. REMOVE vacuum pump. GO to HW15. HW15 CHECK FOR INTAKE MANIFOLD VACUUM AT VMV: BOTH INPUT PORT VACUUM HOSE AND FUEL VAPOR HOSE

Page 3 of 8 EVAP canister purge valve electrically connected. Disconnect both input port vacuum and fuel vapor hoses from intake manifold vacuum source and fuel vapor ports at EVAP canister purge valve. (Refer to the EVAP canister purge valve vacuum schematic at the beginning of this pinpoint test.) Install a vacuum gauge (two gauges or one gauge at a time) to open end of input port vacuum hose and open end of the fuel vapor hose at EVAP canister purge valve. Start engine. Are both vacuum gauge readings greater than 33.77 kpa (10 in-hg)? LEAVE input port vacuum and fuel vapor hoses to the intake manifold at EVAP canister purge valve disconnected. GO to HW16. ISOLATE causes of missing intake manifold vacuum. REPAIR partially unconnected hoses or kinked/blocked hoses to intake manifold. REMOVE vacuum gauge(s). RESTORE vehicle. GO to the Powertrain/Engine Group in the Workshop Manual for base engine vacuum loss. COMPLETE PCM Reset to clear DTCs. GO to HW42. HW16 CHECK FOR INPUT PORT VACUUM HOSE AND FUEL VAPOR HOSE RESTRICTIONS BETWEEN EVAP CANISTER PURGE VALVE AND INTAKE MANIFOLD Disconnect input port vacuum hose and fuel vapor hose from EVAP canister purge valve at intake manifold (other end of hoses are already disconnected). Install a hand vacuum pump to one end of each completely disconnected hose from EVAP canister purge valve to intake manifold. Apply 53 kpa (16 in-hg) of vacuum with vacuum pump. Observe the vacuum reading for 30 seconds. Does the vacuum bleed off immediately? REMOVE vacuum pump. CORRECT minor concerns with input vacuum hose and fuel vapor hose between EVAP canister purge valve and intake manifold. If hoses were OK, REPLACE damaged EVAP canister purge valve. RESTORE vehicle. GO to HW42. REMOVE vacuum pump. REMOVE blockages or minor kinks in input vacuum hose and fuel vapor hose between EVAP canister purge valve and intake manifold. RESTORE vehicle. DRIVE vehicle. GO to HW42. HW17 CHECK VPWR VOLTAGE TO EVAP CANISTER PURGE VALVE Disconnect EVAP canister purge valve harness connector. Measure VPWR circuit voltage at EVAP canister purge valve harness connector to battery negative post. Was voltage greater than 10.5 volts? GO to HW18. REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. HW18 CHECK EVAP CANISTER PURGE VALVE STUCK OPEN CONDITION OR PF SENSOR DAMAGE Disconnect fuel vapor hose from intake manifold at PF sensor. Reconnect the EVAP canister purge valve (electrically). Install a hand-held vacuum pump to intake manifold side of PF sensor. Apply 53 kpa (16 in-hg) of vacuum to open end of PF sensor. Does the EVAP canister purge valve-pf sensor assembly hold vacuum for 20 seconds? LEAVE the vacuum pump connected. GO to HW19. If PF sensor housing is cracked, REPLACE PF sensor. Otherwise, REPLACE fuel vapor hose between EVAP canister purge valve and PF sensor. If fuel vapor hose was OK, REPLACE EVAP canister purge valve. RESTORE vehicle. GO to HW42. HW19 CHECK HOSE BLOCKAGE - EVAP CANISTER PURGE VALVE STUCK CLOSED CONDITION Connect scan tool. Apply 53 kpa (16 in-hg) of vacuum to open end of PF sensor. Access Output Test Mode on the scan tool to cycle EVAP canister purge valve. Did the EVAP canister purge valve open and vacuum reading on the vacuum pump drop (air passes freely) when commanding the output on? REMOVE vacuum pump. GO to HW20. REMOVE the vacuum pump. REMOVE blockages in fuel vapor hose between EVAP canister purge valve and PF sensor. If OK, REPLACE EVAP canister purge valve. RESTORE vehicle. GO to HW42. HW20 CHECK INTAKE MANIFOLD VACUUM TO PF SENSOR Install a vacuum gauge to the open end of fuel vapor hose (intake manifold side) at PF sensor. Start engine. Observe vacuum gauge at idle (for Escort/Tracer application observe vacuum gauge reading at part throttle).

Page 4 of 8 Was the vacuum gauge reading greater than 33.77 kpa (10 in-hg) with engine running? CHECK for small vacuum leaks between PF sensor and intake manifold. REPAIR as necessary. RESTORE vehicle. DRIVE vehicle. GO to HW42. REMOVE blockage, RECONNECT loose fuel vapor hose or REPLACE cracked, split fuel vapor hose between the PF sensor and intake manifold. GO to HW42. If DTC P1443 is still present, GO to HW21. All others: RETURN to Section 3A, Symptom Charts. HW21 CHECK EVAP CANISTER PURGE VALVE RESISTANCE Disconnect EVAP canister purge valve. Measure EVAP canister purge valve resistance. Is the resistance between 30 and 90 ohms? GO to HW22. REPLACE damaged EVAP canister purge valve. RESTORE vehicle. GO to HW42. HW22 CHECK EVAP CANISTER PURGE CIRCUIT FOR SHORT TO VPWR IN HARNESS Measure resistance between PCM test pin 67 or PCM test pin 56 and PCM test pin 71. Is resistance greater than 10,000 ohms? REPLACE PCM. RESTORE vehicle. REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. Access the EVAPPDC PID on the scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until the EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. Access the EVAPPDC PID on the scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until the EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. HW23 CHECK EVAPORATIVE EMISSION SYSTEM LEAK THROUGH EVAPORATIVE EMISSION SERVICE PORT Odors in the engine compartment or near the exhaust system and stalls can be associated to the evaporative emission system. After-market parts and accessories not conforming to evaporative system specifications. Leaks in the evaporative emission system. Blockages in the evaporative emission system. Remove atmospheric vent cap (blue or black) on EVAP canister(s) or canister vent line. Plug (or tape) open vent on EVAP canister(s). Disconnect and plug fuel vapor hose to PF sensor (or EVAP canister purge valve) from intake manifold at the intake manifold vacuum source. Locate evaporative emission test port (marked EVAPORATIVE SERVICE PORT) between EVAP canister purge valve and EVAP canister. If vehicle does not have a test port, GO to Pinpoint Test step HW24. Access the Rotunda Evaporative Emission System Tester 134-00056 or equivalent, including the compressed gas source (nitrogen or argon) and pressure regulator. Perform a Tester Self-Test using the instructions provided with the Tester Kit. Regulate the gas pressure on the Tester to 6.74 kpa (27 in-h 2 O). Install the Rotunda Evaporative Emission System Tester to the test port and follow the system leak test instructions provided with the Tester Kit. If the pressure is not between 6.46 and 6.97 kpa (26 and 28 in-h 2 O), use the ultra-sonic leak detector provided with the Tester Kit to check for leakage at the vehicle's fuel filler cap and filler pipe assembly. Is a leak indicated? REMOVE and VERIFY fuel filler cap according to original equipment specifications. REPLACE damaged fuel filler cap. REINSTALL fuel filler cap and TIGHTEN cap only one eighth turn so that cap initially clicks by sound or touch. REPEAT evaporative emission system leak test using Tester. If the leak is still present, REPAIR or GO to HW24. REPLACE fuel tank, fuel filler pipe, fuel vapor valve or fuel vapor hose between fuel tank and EVAP canister as necessary. RESTORE vehicle. VERIFY a symptom no longer exists. HW24 CHECK EVAPORATIVE EMISSION SYSTEM USING ROTUNDA EVAPORATIVE EMISSION SYSTEM TESTER Remove the fuel filler cap. Install the Rotunda Evaporative Emission System Tester 134-00056 or equivalent, including the compressed gas (nitrogen or argon) and pressure regulator. Tester kit contains all required adapters (Schrader valve and fuel filler cap per vehicle application). For Mustang only: cycle the valve open through output test mode with the scan tool (or disconnect valve harness connection and energize valve using a voltage source). Pressurize the vehicle evaporative emission system at 6.74 kpa (27 in.-h 2 O) using the Evaporative Emission System Tester and the instructions that come with the tester. Is a system leak indicated by the tester red light on?

Page 5 of 8 ALLOW the two-position control on the tester to provide a continuing flow of the gas to the closed evaporative emission system. MAINTAIN 6.74 kpa (27 in.-h 2 O) pressure on the system (monitor tester pressure gauges). GO to HW25. REMOVE Evaporative Emission System Leak Tester. COMPLETE PCM Reset to clear DTCs. Access the EVAPPDC PID on the scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until the EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. RERUN Quick Test. VERIFY a symptom no longer exists. HW25 CHECK FOR FUEL VAPOR HOSE RESTRICTIONS BETWEEN EVAP CANISTER PURGE VALVE, FUEL TANK AND EVAP CANISTER Disconnect and plug the fuel vapor hose from the EVAP canister(s) at EVAP canister purge valve. Reinitiate pressurizing of vehicle evaporative emission system using the Rotunda Evaporative Emission System Tester. Refer to Pinpoint Test Step HW24 for pressurizing instructions. When pressure on the evaporative emission system is stabilized close to 6.74 kpa (27 in-h 2 O), record the reading. Remove the plug at the fuel vapor hose to EVAP canister at the EVAP canister purge valve. Observe pressure gauges on tester. Does the pressure immediately drop? REMOVE plugs. REINSTALL the dust cap (blue or black) on EVAP canister or canister vent line at canister. RESTORE vehicle. GO to HW42. REMOVE blockages and STRAIGHTEN fuel vapor tubes/hoses between fuel tank, EVAP canister purge valve and EVAP canister(s). GO to the Powertrain/Engine System Group, Evaporative Emission section in the Workshop Manual for blockage concerns. REMOVE plugs. REINSTALL the dust cap (blue or black) on EVAP canister. RESTORE the vehicle. GO to HW42. HW27 DTC P1444: CHECK PF SENSOR LOW VOLTAGE TO PCM Continuous Memory Diagnostic Trouble Code (DTC) P1444 indicates that Self-Test has detected a PF sensor circuit input below the minimum. PF sensor circuit short to PWR GND. VPWR open circuit. Damaged purge flow (PF) sensor. Damaged PCM. Check for loose pins or broken wires by pulling moderately on the VPWR circuit at PF sensor harness connector. Repair as necessary. Reconnect PF sensor. Connect scan tool. Key on, engine running. te: PF sensor input range to the PCM is 0.40 to 4.80 volts. Was EVAPPF PID voltage less than 0.40 volt? For EVAPPF PID voltage between 0.20 and 0.40 volt: GO to HW28. For EVAPPF PID voltage less than 0.20 volt: Fault is an intermittent DTC P1444. GO to HW32. GO to HW30. HW28 CHECK FOR OPEN VPWR CIRCUIT IN THE PF SENSOR Allow the vehicle and PF sensor to cool down or warm up to room temperature 13 C to 27 C (55 F to 80 F) before taking a resistance measurement on the PF sensor. This can take 15 to 20 minutes. Measure resistance between VPWR pin and PF, PWR GND pins on the PF sensor. Is resistance greater than 160 ohms between VPWR and PF pins or greater than 190 ohms between VPWR and PWR GND pins? REPLACE damaged PF sensor. RESTORE vehicle. RECORD data from this Pinpoint Test Step. GO to HW42. GO to HW29. HW29 CHECK VPWR FOR OPEN IN HARNESS Measure resistance of VPWR circuit between PCM test pin 71 and PF sensor harness connector. Is resistance less than 5.0 ohms?

Page 6 of 8 LEAVE breakout box installed. For DTC P1444: GO to HW30. For DTC P1445: REPAIR open circuit. RESTORE vehicle. VERIFY a symptom no longer exists. COMPLETE PCM Reset to clear DTCs. GO to HW34. HW30 CHECK FOR SHORT TO PWR GND CIRCUIT IN PF SENSOR Allow the vehicle and PF sensor to cool down or warm up to room temperature (13 C to 27 C (55 F to 80 F)) before taking a resistance measurement on the PF sensor. This can take 15 to 20 minutes. Measure resistance between PWR GND and PF pins on the PF sensor. Is resistance less than 25.50 ohms? REPLACE damaged PF sensor. RESTORE vehicle. GO to HW42. GO to HW31. HW31 CHECK PF CIRCUIT FOR SHORTS TO PWR GND Disconnect scan tool from DLC. Measure resistance between PCM test pin 11 and PCM test pins 24 and 103. Are both resistances greater than 10,000 ohms? REPLACE damaged PCM. RESTORE vehicle. REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. HW32 CHECK PURGE FLOW SENSOR CIRCUIT FOR INTERMITTENT VPWR OPEN OR PWR GND SHORT Observe EVAPPF PID for an indication of a fault while performing the following: Is a fault indicated? Lightly tap on PF sensor; wiggle PF sensor connector and harness between sensor and PCM. A fault is indicated by a sudden change in EVAPPF PID voltage (less than 0.14 volt). ISOLATE fault and REPAIR as necessary. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. Unable to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 with the following data: PF PID and a list of Possible causes. HW33 DTC P1445: CHECK PF SENSOR HIGH VOLTAGE TO PCM Continuous Memory Diagnostic Trouble Code (DTC) P1445 indicates that Self-Test has detected a PF sensor circuit input above the maximum. PF shorted to VPWR. PF open circuit. PWR GND open circuit. Damaged purge flow (PF) sensor. Damaged PCM. Check for loose pins or broken wires by pulling moderately on the PF and PWR GND circuits at PF sensor harness connector. Repair as necessary. Reconnect PF sensor. Connect scan tool. te: PF sensor input to the PCM range is 0.40 to 4.80 volts. Was EVAPPF PID voltage greater than 4.80 volts? GO to HW34. Fault is an intermittent DTC P1445. GO to HW39. HW34 CHECK VPWR RESISTANCE FOR SHORT TO PF CIRCUIT IN PF SENSOR

Page 7 of 8 Allow the vehicle and PF sensor to cool down or warm up to a room temperature 13 C to 27 C (55 F to 8 0 F) before taking a resistance measurement on the PF sensor. This can take 15 to 20 minutes. Measure resistance between VPWR and PF pins on the PF sensor. Is resistance between 40 and 230 ohms? GO to HW35. REPLACE damaged PF sensor. RESTORE vehicle. GO to HW42. HW35 CHECK PF SENSOR VOLTAGE INPUT TO PCM Measure PF circuit voltage at PF sensor harness connector to battery negative post. Was voltage greater than 10.5 volts? GO to HW36. GO to HW37. HW36 CHECK PF CIRCUIT FOR SHORT TO VPWR IN HARNESS Measure resistance between PCM test pin 11 and PCM test pins 24 or 103. Is the voltage greater than 10.5 volts? REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. REPLACE damaged PCM. RESTORE vehicle. HW37 CHECK PF CIRCUIT FOR OPEN IN HARNESS Measure resistance of PF circuit between PCM test pin 11 and PF sensor harness connector. Is the resistance less than 5.0 ohms? GO to HW38. REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. HW38 CHECK PWR GND CIRCUIT FOR OPEN IN HARNESS Measure resistance of PWR GND circuit between PCM test pin 24 or 103 and PF sensor harness connector. Is the resistance less than 5.0 ohms? REPLACE damaged PCM. RESTORE vehicle. REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. HW39 CHECK PURGE FLOW SENSOR CIRCUIT FOR INTERMITTENT PF OPEN OR VPWR SHORT Observe EVAPPF PID for an indication of a fault while performing the following: Is a fault indicated? Lightly tap on PF sensor; wiggle PF sensor connector and harness between sensor and PCM. A fault is indicated by a sudden change in EVAPPF PID voltage (greater than 4.80 volts). ISOLATE fault and REPAIR as necessary. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. UNABLE to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 with the following data: PF PID and a list of Possible causes. HW40 DTC P0443: INSPECT EVAP CANISTER PURGE VALVE CIRCUIT FOR INTERMITTENT FAILURE Continuous Memory Diagnostic Trouble Code (DTC) P0443 may indicate an EVAP canister purge valve circuit failure.

Page 8 of 8 Damaged EVAP canister purge valve. EVAP CANISTER PURGE or VPWR circuit open. Rerun KOEO, KOER Self-Tests and retrieve Continuous Memory DTCs. Is DTC P0443 present in Continuous Memory Self-Test only? GO to HW41. GO to HW1. HW41 CHECK EVAP CANISTER PURGE VALVE CIRCUIT INTERMITTENT OPEN OR SHORT Measure resistance between PCM test pin 67 or PCM test pin 56 and PCM test pin 71, while performing the following: Lightly tap on the EVAP canister purge valve and observe a resistance change. Wiggle the EVAP canister purge valve connector and vehicle harness between the valve and the PCM, observe a resistance change. Does the resistance reading change to below 30 ohms or above 90 ohms (Mustang) or above 38 ohms (Continental, F-Series/E-Series)? ISOLATE fault and REPAIR as necessary. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. UNABLE to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 with the resistance readingsand list of Possible causes. HW42 VERIFICATION OF EVAPORATIVE EMISSION SYSTEM REPAIR USING ROTUNDA EVAPORATIVE EMISSION SYSTEM LEAK TESTER Plug or tape atmospheric vent cap on EVAP canister (if applicable). Remove fuel filler cap at fuel filler pipe. Install Rotunda Evaporative Emission System Leak Tester 134-00056 or equivalent including the nitrogen or argon gas supply and pressure regulator. Disconnect and plug fuel vapor hose to PF sensor (or EVAP canister purge valve on Ranger) from intake manifold at the intake manifold vacuum source. Pressurize the EVAP system at 6.74 kpa (27 in-h 2 O) with tester. Observe tester installation leak self-test for two minutes and then the EVAP system leak test. Listen for a vacuum leak noise and check for substantial fuel vapor odors at isolated areas in the EVAP system. Does the pressure applied to the EVAP system hold? REMOVE plug and RECONNECT fuel vapor hose from PF sensor (or EVAP canister purge valve) at intake manifold vacuum source. REMOVE EVAP System Leak Tester. REINSTALL fuel filler cap. TIGHTEN cap only one eighth turn so that cap initially clicks by sound or touch. COMPLETE PCM Reset to clear DTCs. Access EVAPPDC PID on scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. VERIFY a symptom no longer exists. GO to HW43. HW43 CHECK LOCATION OF EVAPORATIVE EMISSION SYSTEM PRESSURE LEAK Systematically isolate area of potential pressure leak. Close off pressure to EVAP system. Disconnect and plug fuel vapor hose from fuel tank at EVAP canister. Apply controlled pressure at 6.74 kpa (27 in-h 2 O to the EVAP system with the leak tester. If pressure now holds, GO to the Powertrain/Engine Group, Evaporative Emissions Section in the Workshop Manual for EVAP canister diagnosis. If system presure cannot hold, close pressure supply to system. Disconnect and plug fuel vapor hose from EVAP canister at EVAP canister purge valve. Again, apply controlled pressure to the EVAP system. Does the pressure hold? REMOVE plugs. RECONNECT fuel vapor hose at EVAP canister. RETURN to Pinpoint Test Step HW14 to check EVAP canister purge valve integrity on Ranger or Pinpoint Test Step HW18 to check EVAP canister purge valve integrity on Mustang. REMOVE EVAP System Leak Tester. REINSTALL fuel filler cap. COMPLETE PCM Reset to clear DTCs. Access EVAPPDC PID on scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. RERUN Quick Test. VERIFY a symptom no longer exists. REMOVE plugs. CHECK for fuel vapor hose cracks or fuel vapor valve damage. EXAMINE and SECURE fuel vapor hose connections to components. REPAIR or REPLACE as necessary. REMOVE EVAP System Leak Tester. REINSTALL fuel filler cap. COMPLETE PCM Reset to clear DTCs. Access EVAPPDC PID on scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. VERIFY a symptom no longer exists.