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DTC Diagnosis Procedure
1.RETIGHTEN A/F SENSOR 1
Loosen and retighten the A/F sensor 1. Refer to Exploded View.
: .
 
2.CHECK EXHAUST GAS LEAK
  1. Start engine and run it at idle.
  2. Listen for an exhaust gas leak before three way catalyst (manifold).
Is exhaust gas leak detected?
Repair or replace.
.
 
3.CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
Is intake air leak detected?
Repair or replace.
.
 
4.CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE
  1. Clear the mixture ratio self-learning value. Refer to DescriptionDescription.
  2. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171 or P172 detected? Is it difficult to start engine?
Perform trouble diagnosis for DTC P0171 or P0172. Refer to DTC Diagnosis Procedure. or DTC Diagnosis Procedure
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5.CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
  1. Disconnect A/F sensor 1 harness connector.
  2. Turn ignition switch ON.
  3. Check the voltage between A/F sensor 1 harness connector and ground.
    +–Voltage
    A/F sensor 1
    ConnectorTerminal
    F184GroundBattery voltage
Is the inspection result normal?
.
Repair or replace error-detected parts.
 
6.CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
  1. Turn ignition switch OFF.
  2. Disconnect ECM harness connector.
  3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
    +–Continuity
    A/F sensor 1ECM
    ConnectorTerminalConnectorTerminal
    F181F5156Existed
    260
  4. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.
    +–Continuity
    A/F sensor 1
    ConnectorTerminal
    F181GroundNot existed
    2
    +–Continuity
    ECM
    ConnectorTerminal
    F5156GroundNot existed
    60
  5. Also check harness for short to power.
Is the inspection result normal?
.
Repair or replace error-detected parts.
 
7.CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER
Refer to Component Inspection.
Is the inspection result normal?
.
.
 
8.CHECK MASS AIR FLOW SENSOR
Refer to Component Inspection.
Is the inspection result normal?
.
Replace mass air flow sensor. Refer to Exploded View.
 
9.CHECK PCV VALVE
CRANKCASE VENTILATION : Periodic Maintenance. Refer to POSITIVE CRANKCASE VENTILATION : Periodic Maintenance.
Is the inspection result normal?
.
Repair or replace PCV valve. Refer to Component Parts Location.
 
10.CHECK INTERMITTENT INCIDENT
Perform Refer to Intermittent IncidentIntermittent Incident.
Is the inspection result normal?
.
Repair or replace.
 
11.REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace air fuel ratio (A/F) sensor 1. Refer to Exploded View.
: INSPECTION END