Component Description DTC P1273 A/F SENSOR 1 The A/F sensor 1 is a planar dual-cell limit current sensor. The sensor element of the A/F sensor 1 is the combination of a Nernst concentration cell (sensor cell) with an oxygen-pump cell, which transports ions. It has a heater in the element. The sensor is capable of precise measurement = 1, but also in the lean and rich range. Together with its control electronics, the sensor outputs a clear, continuous signal throughout a wide range (0.7 < < air). The exhaust gas components diffuse through the diffusion gap at the electrode of the oxygen pump and Nernst concentration cell, where they are brought to thermodynamic balance. PFP:22693 UBS00BDP SEF579Z An electronic circuit controls the pump current through the oxygenpump cell so that the composition of the exhaust gas in the diffusion gap remains constant at = 1. Therefore, the A/F sensor 1 is able to indicate air-fuel ratio by this pumping of current. In addition, a heater is integrated in the sensor to ensure the required operating temperature of 700-800 C (1,292-1,472 F). CONSULT-II Reference Value in Data Monitor Mode Specification data are reference values. A/F SEN1 (B1) MONITOR ITEM CONDITION SPECIFICATION On Board Diagnosis Logic Engine: After warming up EC-462 UBS00BDQ UBS00BDR To judge the malfunction, the A/F signal computed by ECM from the air fuel ratio (A/F) sensor 1 signal is monitored not to be shifted lean side or rich side. When the A/F signal is shifting to the lean side, the malfunction will be detected. DTC No. P1273 1273 Trouble diagnosis name Air fuel ratio (A/F) sensor 1 lean shift monitoring DTC Confirmation Procedure DTC detecting condition Maintaining engine speed at 2,000 rpm The output voltage computed by ECM from the A/ F sensor 1 signal is shifted to the lean side for a specified period. Fluctuates around 1.5V Possible Cause UBS00BDS If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test. TESTING CONDITION: Before performing the following procedure, confirm that battery voltage is more than 11V at idle. WITH CONSULT-II 2. Select A/F SEN1 (B1) P1273 of A/F SEN1 in DTC WORK SUPPORT mode. 3. Touch START. SEF580Z Air fuel ratio (A/F) sensor 1 Air fuel ratio (A/F) sensor heater 1 Fuel pressure Fuel injectors Intake air leaks
4. Maintain the following conditions continuously until TESTING changes to COMPLETED. (It will take approximately 400 to 800 seconds.) Keep the accelerator pedal as steady as possible. A EC ENG SPEED B/FUEL SCHDL Selector lever Below 3,200 rpm Below 13.6 msec P or N position C If TESTING is not displayed after 20 minutes, retry from step 2. SEF567Z D E F G 5. Make sure that OK is displayed after touching SELF-DIAG RESULTS. If NG is displayed, go to EC-466, "Diagnostic Procedure". SEF568Z H I J SEF569Z K Overall Function Check UBS00BDT Use this procedure to check the overall function of the A/F sensor 1 circuit. During this check, a 1st trip DTC might not be confirmed. WITH GST 2. Drive the vehicle at a speed of 80 km/h (50 MPH) for a few minutes in D position with OD OFF (A/T) or 3rd position (M/T). Keep accelerator pedal as steady as possible during the cruising. 3. Set D position with OD ON (A/T) or 4th position (M/T), then release the accelerator pedal fully until the vehicle speed decreases to 50 km/h (30 MPH). Never apply brake during releasing the accelerator pedal. 4. Repeat steps 2 to 3 five times. 5. Stop the vehicle and turn ignition switch OFF. 6. Wait at least 10 seconds and restart engine. 7. Repeat steps 2 to 3 five times. 8. Stop the vehicle and connect GST to the vehicle. 9. Make sure that no DTC is displayed. L M EC-463
If the DTC is displayed, go to EC-466, "Diagnostic Procedure". EC-464
Wiring Diagram DTC P1273 A/F SENSOR 1 UBS00BDU A EC C D E F G H I J K L M BBWA0700E EC-465
Specification data are reference values and are measured between each terminal and ground. CAUTION: Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground. TERMI- NAL NO. WIRE COLOR Diagnostic Procedure 1. RETIGHTEN AIR FUEL RATIO (A/F) SENSOR 1 ITEM CONDITION DATA (DC Voltage) 16 OR/L Approximately 3.1V [Engine is running] 35 B/Y Approximately 2.6V A/F sensor 1 Warm-up condition 56 OR 2-3V Idle speed 75 W/L 2-3V 1. Turn ignition switch OFF. 2. Loosen and retighten the air fuel ratio (A/F) sensor 1. Tightening torque: 40-60 N-m (4.1-6.1 kg-m, 30-44 ft-lb) UBS00BDV >> GO TO 2. EC-466
2. CLEAR THE SELF-LEARNING DATA. With CONSULT-II 2. Select SELF-LEARNING CONT in WORK SUPPORT mode with CONSULT-II. 3. Clear the self-learning control coefficient by touching CLEAR. 4. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171 detected? Is it difficult to start engine? A EC C D E Without CONSULT-II 2. Turn ignition switch OFF. 3. Disconnect mass air flow sensor harness connector, and restart and run engine for at least 3 seconds at idle speed. 4. Stop engine and reconnect mass air flow sensor harness connector. 5. Make sure DTC P0102 is displayed. 6. Erase the DTC memory. Refer to EC-64, "HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION". 7. Make sure DTC P0000 is displayed. 8. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171 detected? Is it difficult to start engine? Yes or No Yes >> Perform trouble diagnosis for DTC P0171. Refer to EC-212. No >> GO TO 3. SEF652Y BBIA0150E F G H I J K L M EC-467
3. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT 1. Turn ignition switch OFF. 2. Disconnect ECM harness connector and A/F sensor 1 harness connector. 3. Check harness continuity between the following terminals. Refer to Wiring Diagram. ECM terminal A/F sensor 1 terminal 16 1 35 5 56 6 75 2 BBIA0140E Continuity should exist. 4. Check harness continuity between ECM terminals 16, 35, 56, 75 or A/F sensor 1 terminals 1, 2, 5, 6 and ground. Refer to Wiring Diagram. Continuity should not exist. 5. Also check harness for short to power. OK or NG OK >> GO TO 4. NG >> Repair open circuit or short to ground or short to power in harness or connectors. 4. CHECK A/F SENSOR 1 HEATER Refer to EC-356, "Component Inspection". OK or NG OK >> GO TO 5. NG >> Replace A/F sensor 1. 5. CHECK INTERMITTENT INCIDENT Perform EC-140, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT". OK or NG OK >> Replace A/F sensor 1. NG >> Repair or replace. Removal and Installation AIR FUEL RATIO SENSOR 1 Refer to EM-13, "Removal and Installation". UBS00BDW EC-468