Diagnostic Procedure

1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. See Figure .

   Refer to GROUND INSPECTION  .

OK or NG

1. OK: go to 2.
2. NG: Repair or replace ground connections.

Loosen and retighten corresponding heated oxygen sensor 1. See Figure .

Tightening torque: 45 N.m (4.6 kg-m, 33 ft-lb) 

1. Go to 3.

With CONSULT-II 

1. Start engine and warm it up to normal operating temperature.
2. Select SELF-LEARNING CONT in WORK SUPPORT mode with CONSULT-II. See Figure .
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 or P0174 detected? 

   Is it difficult to start engine? 

Without CONSULT-II 

1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
3. Disconnect mass air flow sensor harness connector, and restart and run engine for at least 5 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 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 or P0174 detected? 

   Is it difficult to start engine? 

   For mass air flow sensor & intake air temperature sensor location, see Figure .

Yes or No

1. Yes: Perform trouble diagnosis for DTC P0171, P0174. Refer to DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION  .
2. No: go to 4.

Refer to COMPONENT INSPECTION  .

OK or NG

1. OK: go to 5.
2. NG: Replace malfunctioning heated oxygen sensor 1.

Refer to COMPONENT INSPECTION  .

OK or NG

1. OK: go to 6.
2. NG: Replace malfunctioning heated oxygen sensor 1.

Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT  .

For circuit, Refer to WIRING DIAGRAM  .

1. Inspection end