P0038

P0037, P0038 HO2S2 Heater

Description

System Description





The ECM performs ON/OFF control of the heated oxygen sensor 2 heater corresponding to the engine speed, amount of intake air and engine coolant temperature.

Operation






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 test.

TESTING CONDITION:

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

with SDT

1) Start engine and warm it up to the normal operating temperature.
2) Turn ignition switch OFF and wait at least 10 seconds.
3) Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
4) Let engine idle for 1 minute.
5) Check 1st trip DTC.
6) If 1st trip DTC is detected, go to "Diagnosis Procedure".

with GST

Follow the procedure "WITH SDT" above.

Diagnosis Procedure

1. CHECK GROUND CONNECTIONS

1 Turn ignition switch OFF.
2 Loosen and retighten two 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 HO2S2 POWER SUPPLY CIRCUIT

1 Disconnect heated oxygen sensor 2 harness connector.





2 Turn ignition switch ON.
3 Check voltage between HO2S2 terminal 3 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 connector E119
- 15 A fuse (No.54)
- Harness for open or short between heated oxygen sensor 2 and fuse


Repair open circuit, short to ground or short to power in harness or connectors.

4. CHECK HO2S2 OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1 Turn ignition switch OFF.
2 Disconnect ECM harness connector.
3 Check harness continuity between ECM terminal 25 and HO2S2 terminal 2.
Refer to Wiring Diagram.






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

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

5. CHECK HEATED OXYGEN SENSOR 2 HEATER

Refer to "Component Inspection".

OK or NG
OK
GO TO 6.
NG
Replace heated oxygen sensor 2. [Exhaust System: Exploded View] Exploded View.

6. CHECK INTERMITTENT INCIDENT

Refer to [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.


INSPECTION END

Component Inspection

Heated Oxygen Sensor 2 Heater

1) Check resistance between HO2S2 terminals as follows.











2) If NG, replace heated oxygen sensor 2.

CAUTION:

- Discard any heated oxygen 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 oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant (commercial service tool).