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DTC P0038 [L3 Turbo]

id0102b7802300

DTC P0038 | HO2S heater circuit high input
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DETECTION CONDITION | • The PCM monitors the HO2S heater output voltage. If the PCM turns the HO2S heater off but the HO2S heater circuit voltage remains high the PCM determines that the HO2S heater circuit has a malfunction. Diagnostic support note • This is a continuous monitor (A/F sensor heater, HO2S heater). • The MIL illuminates if the 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 the PCM detects the above malfunction condition during the first drive cycle. • FREEZE FRAME DATA is available. • DTCs are stored in the PCM memory.
POSSIBLE CAUSE | • HO2S heater malfunction • Connector or terminal malfunction • Short to power supply in the wiring harness between HO2S terminal D and PCM terminal 4Z • PCM malfunction

Diagnostic procedure

STEP | INSPECTION | ACTION
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1 | VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS 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 Information availability. • Is any related Service Information available? | Yes | Perform repair or diagnosis according to the available Service information. If the vehicle is not repaired, go to the next step.
No | Go to the next step.
3 | INSPECT HO2S CONNECTOR FOR POOR CONNECTION • Turn the ignition switch off. • Disconnect the HO2S connector. • Inspect for poor connection (such as damaged/pulled-out pins, and 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 POWER CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND • Turn the ignition switch to the ON position (Engine off). • Measure the voltage between 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 a possible open circuit or short to ground, then go to Step 9.
5 | INSPECT HO2S HEATER CONTROL CIRCUIT FOR SHORT TO GROUND • Turn the ignition switch off. • Inspect for continuity between HO2S terminal D (wiring harness-side) and body ground. • Is there continuity? | Yes | Repair or replace the wiring harness for a possible short to ground, then go to Step 9.
No | Go to the next step.
6 | INSPECT HO2S HEATER • Inspect the HO2S heater. (See AIR FUEL RATIO (A/F) SENSOR, HEATED OXYGEN SENSOR (HO2S) INSPECTION [L3 Turbo].) • Is there any malfunction? | Yes | Replace the HO2S, then go to Step 9. (See EXHAUST SYSTEM REMOVAL/INSTALLATION [L3 Turbo].)
No | Go to the next step.
7 | INSPECT PCM CONNECTOR FOR POOR CONNECTION • Turn the ignition switch off. • Disconnect the PCM connector. • Inspect for poor connection (such as damaged/pulled-out pins, and corrosion). • Is there any malfunction? | Yes | Repair or replace the terminal, then go to Step 9.
No | Go to the next step.
8 | INSPECT HO2S HEATER CONTROL CIRCUIT FOR OPEN CIRCUIT • Turn the ignition switch off. • Inspect for continuity between HO2S terminal D (wiring harness-side) and PCM terminal 4Z (wiring harness-side). • Is there continuity? | Yes | Go to the next step.
No | Repair or replace the wiring harness for a possible open circuit, then go to the next step.
9 | VERIFY TROUBLESHOOTING OF DTC P0038 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the WDS or equivalent. • Perform the A/F sensor heater, HO2S heater, A/F sensor, HO2S, and TWC Repair Verification Drive Mode. (See OBD DRIVE MODE [L3 Turbo].) • Is the PENDING CODE for this DTC present? | Yes | Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L3 Turbo].)
No | Go to the next step.
10 | VERIFY AFTER REPAIR PROCEDURE • Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE [L3 Turbo].) • Are any DTCs present? | Yes | Go to the applicable DTC inspection. (See DTC TABLE [L3 Turbo].)
No | DTC troubleshooting completed.