DTC P0038 [L8, LF]

id0102b1802300

DTC P0038

HO2S heater circuit high input

DETECTION CONDITION

•  If the input voltage to the HO2S heater drive terminal in the PCM is high for 0.5 s or more even though the HO2S is duty-controlled at 10% or more by the PCM.

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 (Mode 2/Mode 12) is available.

•  The DTC is stored in the PCM memory.

POSSIBLE CAUSE

•  HO2S connector or terminals malfunction

•  HO2S heater malfunction

•  PCM connector or terminals malfunction

•  Short to power supply in wiring harness between HO2S terminal D and PCM terminal 2BE

•  PCM malfunction

DTC P0038	HO2S heater circuit high input
DETECTION CONDITION	• If the input voltage to the HO2S heater drive terminal in the PCM is high for 0.5 s or more even though the HO2S is duty-controlled at 10% or more by the PCM. 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 (Mode 2/Mode 12) is available. • The DTC is stored in the PCM memory.
POSSIBLE CAUSE	• HO2S connector or terminals malfunction • HO2S heater malfunction • PCM connector or terminals malfunction • Short to power supply in wiring harness between HO2S terminal D and PCM terminal 2BE • PCM malfunction

Diagnostic procedure

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA (MODE 12) AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED • Have the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor heater, HO2S heater related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS on repair order, then go to the next step.
2	VERIFY RELATED SERVICE 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.
2		No	Go to the next step.
3	INSPECT HO2S CONNECTOR AND TERMINALS • 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 connector or terminals, then go to Step 7.
3		No	Go to the next step.
4	INSPECT HO2S HEATER • Inspect the HO2S heater. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION [L8, LF].) • Is there any malfunction?	Yes	Replace the HO2S, then go to Step 7. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [L8, LF].)
4		No	Go to the next step.
5	INSPECT PCM CONNECTOR AND TERMINALS • 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 connector or terminals, then go to Step 7.
5		No	Go to the next step.
6	INSPECT HO2S HEATER CIRCUIT FOR SHORT TO POWER SUPPLY • HO2S and PCM connectors are disconnected. • Turn the ignition switch to the ON position (engine off). • Measure the voltage between HO2S terminal D (wiring harness-side) and body ground. • Is there any voltage?	Yes	Repair or replace the wiring harness for a possible short to power supply, then go to the next step.
6		No	Go to the next step.
7	VERIFY DTC TROUBLESHOOTING COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE [L8, LF].) • Perform the KOEO/KOER self test. (See KOEO/KOER SELF TEST [L8, LF].) • Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L8, LF].)
7		No	Go to the next step.
8	VERIFY AFTER REPAIR PROCEDURE • Perform the “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [L8, LF].) • Are any DTCs present?	Yes	Go to the applicable DTC troubleshooting. (See DTC TABLE [L8, LF].)
8		No	DTC troubleshooting completed.