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DTC P0038 [L3]

BME010200001W04

DTC P0038 | Rear HO2S heater circuit high input
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DETECTION CONDITION | • PCM monitors rear HO2S heater control signal at PCM terminal 4D. If PCM turns rear HO2S heater on but rear HO2S heater circuit has high voltage, PCM determines that 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 the DTC for the same malfunction has been stored in the 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 | • Short to power circuit between rear HO2S terminal D and PCM terminal 4D • Rear HO2S or PCM terminal is shorted • PCM malfunction • Rear HO2S malfunction

Diagnostic procedure

STEP | INSPECTION | ACTION
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1 | PERFORM DTC CONFIRMATION PROCEDURE • Perform DTC CONFIRMATION PROCEDURE. (See DTC CONFIRMATION PROCEDURE [L3].) • Is same DTC present? | Yes | Go to next step.
No | Intermittent concern exists. Go to INTERMITTENT CONCERN TROUBLESHOOTING procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING [L3].)
2 | INSPECT REAR HO2S TERMINAL • Turn ignition key to OFF. • Disconnect rear HO2S connector. • Check for bent terminals • Is there any malfunction? | Yes | Repair or replace terminal, then go to Step 6.
No | Go to next step.
3 | INSPECT REAR HO2S HEATER • Inspect rear HO2S heater. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION [L3].) • Is rear HO2S heater okay? | Yes | Go to next step.
No | Replace the rear HO2S, then go to Step 6.
4 | INSPECT PCM TERMINAL • Disconnect PCM connector. • Check for bent terminals. • Is there any malfunction? | Yes | Repair terminal, then go to Step 6.
No | Go to next step.
5 | INSPECT REAR HO2S HEATER CONTROL CIRCUIT FOR SHORT TO POWER • Turn ignition key to ON (Engine OFF). • Measure voltage between rear HO2S terminal D (harness-side) and body ground. • Is voltage B+? | Yes | Repair or replace harness for shot to power circuit, then go to next step.
No | Go to next step.
6 | VERIFY TROUBLESHOOTING OF DTC P0038 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear DTC from PCM memory using WDS or equivalent. • Perform KOEO/KOER self-test. (See KOEO/KOER SELF-TEST PROCEDURE [L3].)
• Is same DTC present?
Yes
Replace PCM, then go to next step.
(See PCM REMOVAL/INSTALLATION [L3].)
No | Go to next step.
7 | VERIFY AFTER REPAIR PROCEDURE • Perform "After Repair Procedure". (See AFTER REPAIR PROCEDURE [L3].) • Is there any DTC present? | Yes | Go to applicable DTC troubleshooting. (See DTC TABLE [L3].)
No | Troubleshooting completed.