DTC P0037 [L3]

BME010201084203

DTC P0037

Rear HO2S heater circuit low input

DETECTION CONDITION

• The PCM monitors the rear HO2S heater control signal at PCM terminal 4D. If the PCM turns the rear HO2S heater off but the rear HO2S heater circuit has low voltage, the PCM determines that the rear HO2S heater circuit has malfunction.
Diagnostic support note
• This is an intermittent monitor (O2 sensor heater).
• MIL illuminates if PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for the same malfunction has been stored in PCM.
• PENDING CODE is available if PCM detects the above malfunction condition.
• FREEZE FRAME DATA is available.
• DTC is stored in PCM memory.

POSSIBLE CAUSE

• Rear HO2S malfunction
• Open circuit between the ignition switch and rear HO2S terminal C
• Open circuit between the rear HO2S terminal D and PCM terminal 4D
• Short to ground circuit between rear HO2S terminal D and PCM terminal 4D
• Poor connection at rear HO2S or PCM connector
• PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
PERFORM DTC CONFIRMATION PROCEDURE
• Perform DTC CONFIRMATION PROCEDURE.
• Is the same DTC present?
Yes
Go to the next step.
No
Intermittent concern exists. Go to INTERMITTENT CONCERN TROUBLESHOOTING procedure.
2
INSPECT POOR CONNECTION OF REAR HO2S CONNECTOR
• Turn the ignition switch off.
• Disconnect the rear 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 8.
No
Go to the next step.
3
INSPECT REAR HO2S HEATER
• Inspect the rear HO2S heater.
• Is the rear HO2S heater normal?
Yes
Go to the next step.
No
Replace the rear HO2S, then go to Step 8.
4
INSPECT REAR HO2S HEATER POWER CIRCUIT FOR OPEN CIRCUIT
• Turn the ignition switch to the ON position (Engine off).
• Measure the voltage between rear HO2S terminal C (wiring 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 8.
5
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 terminal, then go to Step 8.
No
Go to the next step.
6
INSPECT REAR HO2S HEATER CONTROL CIRCUIT FOR SHORT TO GROUND
• Inspect for continuity between rear 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 8.
No
Go to the next step.
7
INSPECT HREAR HO2S HEATER CONTROL CIRCUIT FOR OPEN CIRCUIT
• Inspect for continuity between rear HO2S terminal D (wiring harness-side) and PCM terminal 4D.
• 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.
8
VERIFY TROUBLESHOOTING OF DTC P0037 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 same DTC present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
9
VERIFY AFTER REPAIR PROCEDURE
• Perform "After Repair Procedure".
• Is there any DTC present?
Yes
Go to the applicable DTC inspection.
No
Troubleshooting completed.