P0031

P0031, P0032, P0051, P0052 A/F Sensor 1 Heater

Description

System Description





The ECM performs ON/OFF duty control of the A/F sensor 1 heater corresponding to the engine operating condition to keep the temperature of A/F sensor 1 element within the specified range.

On Board Diagnosis Logic






DTC Confirmation Procedure

NOTE:

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next step.

1) Turn ignition switch OFF and wait at least 10 seconds.
2) Turn ignition switch ON.
3) Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is between 10.5 V and 16 V at idle.

1 Start engine and let it idle for at least 10 seconds.
2 Check 1st trip DTC.
3 If 1st trip DTC is detected, go to "Diagnosis Procedure".

Diagnosis Procedure

1. CHECK GROUND CONNECTIONS

1 Turn ignition switch OFF.
2 Loosen and retighten three ground screws on the body. Refer to [Power Supply and Ground Circuit Check] Power Supply and Ground Circuit Check.






OK or NG
OK
GO TO 2.
NG
Repair or Replace ground connections.

2. CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT

1 Disconnect air fuel ratio (A/F) sensor 1 harness connector.





2 Turn ignition switch ON.
3 Check voltage between air fuel ratio sensor 1 terminal 4 and ground with SDT or tester.











OK or NG
OK
GO TO 4.
NG
GO TO 3.

3. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors E2, F32
- IPDM E/R harness connector E119
- 15 A fuse (No.54)
- Harness for open or short between air fuel ratio sensor 1 and fuse


Repair or replace harness or connectors.

4. CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER OUTPUT SIGNAL CIRCUIT

1 Turn ignition switch OFF.
2 Disconnect ECM harness connector.
3 Check harness continuity between ECM terminal 2 (bank 1) or 24, 43 (bank 2) and air fuel ratio (A/F) sensor 1 terminal 3.
Refer to Wiring Diagram.






4 Also check harness for short to ground or short to power.

OK or NG
OK
GO TO 5.
NG
Repair open circuit or short to ground or short to power in harness or connectors.

5. CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER

Refer to "Component Inspection".

OK or NG
OK
GO TO 6.
NG
GO TO 7.

6. CHECK INTERMITTENT INCIDENT

Perform [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.

OK or NG
OK
GO TO 7.
NG
Repair or replace.

7. REPLACE AIR FUEL RATIO (A/F) SENSOR 1

Replace malfunctioning air fuel ratio (A/F) sensor 1. Refer to [Exhaust Manifold and Three Way Catalyst: Exploded View [VQ40DE] Exhaust Manifold and Three Way Catalyst Exploded View ].

CAUTION:
- Discard any air fuel ratio (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 air fuel ratio (A/F) sensor, clean exhaust system threads using Heated Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.


INSPECTION END

Component Inspection

A/F Sensor 1 Heater

1) Check resistance between A/F sensor 1 terminals as follows.











2) If NG, replace air fuel ratio (A/F) sensor 1.

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 Heated Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.