DTC P0031 [L3 R.H.D.]

id0102a2802000

DTC P0031

HO2S heater circuit low input

DETECTION CONDITION

• The PCM monitors the HO2S heater control signal at PCM terminal 86. If the PCM turns the HO2S heater off but the HO2S heater circuit has low voltage, the PCM determines that the HO2S heater circuit has a malfunction.
Note
• The HO2S heater is controlled by duty signal.
Diagnostic support note
• The MIL illuminates if the PCM detects above malfunction condition in two consecutive drive cycles or in one drive cycle if the DTC for the same malfunction has been stored in the PCM.
• The PENDING CODE is available if the PCM detects above malfunction condition during first drive cycle.
• FREEZE FRAME DATA is available.
• The DTC is stored in the PCM memory.

POSSIBLE CAUSE

• HO2S malfunction
• Open circuit in wiring harness between ignition switch and HO2S terminal C
• Open circuit in wiring harness between HO2S terminal D and PCM terminal 86
• Short to ground in wiring harness between HO2S terminal D and PCM terminal 86
• Poor connection at HO2S or PCM connector
• PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
• Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2
VERIFY RELATED REPAIR INFORMATION AVAILABILITY
• Verify related service repair information availability.
• Is any related repair information available?
Yes
Perform repair or diagnosis according to the available repair information.
• If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
INSPECT POOR CONNECTION OF HO2S CONNECTOR
• Turn the ignition switch off.
• Disconnect HO2S connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 9.
No
Go to the next step.
4
INSPECT HO2S HEATER
• Inspect the HO2S heater.
• Is the HO2S heater normal?
Yes
Go to the next step.
No
Replace the HO2S, then go to Step 9.
5
INSPECT POWER CIRCUIT OF HO2S HEATER FOR OPEN CIRCUIT
• Turn the ignition switch to the ON position (engine off).
• Measure voltage between HO2S terminal C (harness-side) and body ground.
• Is the voltage B+?
Yes
Go to the next step.
No
Repair or replace the wiring harness for open circuit, then go to Step 9.
6
INSPECT POOR CONNECTION OF PCM CONNECTOR
• Turn the ignition switch off.
• Disconnect the PCM connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is there any malfunction?
Yes
Repair the terminals, then go to Step 9.
No
Go to the next step.
7
INSPECT CONTROL CIRCUIT OF HO2S HEATER FOR SHORT TO GROUND
• Inspect for continuity between HO2S terminal D (wiring harness-side) and body ground.
• Is there continuity?
Yes
Repair or replace the wiring harness for short to ground, then go to Step 9.
No
Go to the next step.
8
INSPECT CONTROL CIRCUIT OF HO2S HEATER FOR OPEN CIRCUIT
• Inspect for continuity between HO2S terminal D (wiring harness-side) and PCM terminal 86.
• Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness for open circuit, then go to the next step.
9
VERIFY TROUBLESHOOTING OF DTC P0031 COMPLETED
• Make sure to reconnect all disconnected connectors.
• Clear the DTC from the PCM memory using the WDS or equivalent.
• Perform KOEO/KOER self test.
• Is the PENDING CODE for this DTC present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
10
VERIFY AFTER REPAIR PROCEDURE
• Perform the "AFTER REPAIR PROCEDURE".
• Are any DTCs present?
Yes
Go to the applicable DTC troubleshooting.
No
Troubleshooting completed.