Diagnosis Procedure
- RETIGHTEN A/F SENSOR 1
Loosen and retighten the A/F sensor 1. Refer to "EXPLODED VIEW ".
: GO TO 2.
- CHECK EXHAUST GAS LEAK
- Start engine and run it at idle.
- Listen for an exhaust gas leak before three way catalyst 1.
Is exhaust gas leak detected?
YES: Repair or replace.
NO: GO TO 3.
- CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
Is intake air leak detected?
YES: Repair or replace.
NO: GO TO 4.
- CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE
- Clear the mixture ratio self-learning value. Refer to "WORK PROCEDURE ".
- Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171 or P0172 detected? Is it difficult to start engine?
YES: Perform trouble diagnosis for DTC P0171 or P0172. Refer to "DTC LOGIC " or "DTC LOGIC ".
NO: GO TO 5.
- CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY
- Turn ignition switch OFF.
- Disconnect A/F sensor 1 harness connector.
- Turn ignition switch ON.
- Check the voltage between A/F sensor 1 harness connector and ground.
+ - Voltage A/F sensor 1 Connector Terminal F70 4 Ground Battery voltage Is the inspection result normal?
YES: GO TO 7.
NO: GO TO 6.
- CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
- Turn ignition switch OFF.
- Disconnect IPDM E/R harness connector.
- Check the continuity between A/F sensor 1 harness connector and IPDM E/R harness connector.
+ - Continuity A/F sensor 1 IPDM E/R Connector Terminal Connector Terminal F70 4 E14 36 Existed - Also check harness for short to ground.
Is the inspection result normal?
YES: Perform the trouble diagnosis for power supply circuit.
NO: Repair or replace error-detected parts.
- CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
- Turn ignition switch OFF.
- Disconnect ECM harness connector.
- Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
+ - Continuity A/F sensor 1 ECM Connector Terminal Connector Terminal F70 1 F25 21 Existed 2 25 - Check the continuity between A/F sensor 1 harness connector and ground or ECM harness connector and ground.
+ - Continuity A/F sensor 1 Connector Terminal F70 1 Ground Not existed 2 + - Continuity ECM Connector Terminal F25 21 Ground Not existed 25 - Also check harness for short to power.
Is the inspection result normal?
YES: GO TO 8.
NO: Repair or replace error-detected parts.
- CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER
Check the air fuel ratio (A/F) sensor 1 heater. Refer to "COMPONENT INSPECTION ".
Is the inspection result normal?
YES: GO TO 9.
NO: GO TO 12.
- CHECK MASS AIR FLOW SENSOR
Check the mass air flow sensor. Refer to "COMPONENT INSPECTION ".
Is the inspection result normal?
YES: GO TO 10.
NO: Replace mass air flow sensor. Refer to "EXPLODED VIEW ".
- CHECK PCV VALVE
Check the PCV valve. Refer to "INSPECTION ".
Is the inspection result normal?
YES: GO TO 11.
NO: Repair or replace PCV valve. Refer to "EXPLODED VIEW ".
- CHECK INTERMITTENT INCIDENT
Perform "INTERMITTENT INCIDENT ".
Is the inspection result normal?
YES: GO TO 12.
NO: Repair or replace error-detected parts.
- REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace malfunctioning air fuel ratio (A/F) sensor 1. Refer to "EXPLODED VIEW ".
CAUTION:- Discard any A/F sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
- Before installing new A/F sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner (commercial service tool) and approved anti-seize lubricant (commercial service tool).
: INSPECTION END