DTC P0037 [L8, LF]

id0102b1802200

DTC P0037

HO2S heater circuit low input

DETECTION CONDITION

•  If the input voltage to the HO2S heater drive terminal in the PCM is low for 0.5 s or more even though the HO2S is duty-controlled at under 90% 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

•  Open circuit or short to ground in wiring harness between ignition relay and HO2S terminal C

―  Short to ground in wiring harness between ignition relay and HO2S terminal C

―  ENGINE 15 A fuse malfunction

―  Open circuit in wiring harness between ignition relay and HO2S terminal C

•  HO2S heater malfunction

•  PCM connector or terminals malfunction

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

•  Open circuit in wiring harness between HO2S terminal D and PCM terminal 2BE

•  PCM malfunction

DTC P0037	HO2S heater circuit low input
DETECTION CONDITION	• If the input voltage to the HO2S heater drive terminal in the PCM is low for 0.5 s or more even though the HO2S is duty-controlled at under 90% 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 • Open circuit or short to ground in wiring harness between ignition relay and HO2S terminal C ― Short to ground in wiring harness between ignition relay and HO2S terminal C ― ENGINE 15 A fuse malfunction ― Open circuit in wiring harness between ignition relay and HO2S terminal C • HO2S heater malfunction • PCM connector or terminals malfunction • Short to ground in wiring harness between HO2S terminal D and PCM terminal 2BE • Open circuit 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 9.
3		No	Go to the next step.
4	INSPECT HO2S HEATER CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND • HO2S connector is disconnected. • Turn the ignition switch to the ON position (engine off). • Measure the voltage at HO2S terminal C (wiring harness-side). • Is the voltage B+?	Yes	Go to the next step.
4		No	Inspect the ENGINE 15 A fuse. If the fuse is melt: • Repair or replace the wiring harness for a possible short to ground, then replace the fuse. If the fuse is deterioration: • Replace the fuse. If the fuse is normal: • Repair or replace the wiring harness for a possible open circuit. Go to Step 9.
5	INSPECT HO2S HEATER • Turn the ignition switch off. • Inspect the HO2S heater. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION [L8, LF].) • Is there any malfunction?	Yes	Replace the HO2S, then go to Step 9. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [L8, LF].)
5		No	Go to the next step.
6	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 9.
6		No	Go to the next step.
7	INSPECT HO2S HEATER CIRCUIT FOR SHORT TO GROUND • HO2S and PCM connectors are disconnected. • 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.
7		No	Go to the next step.
8	INSPECT HO2S HEATER CIRCUIT FOR OPEN CIRCUIT • HO2S and PCM connectors are disconnected. • Inspect for continuity between HO2S terminal D (wiring harness-side) and PCM terminal 2BE (wiring harness-side). • Is there continuity?	Yes	Go to the next step.
8		No	Repair or replace the wiring harness for a possible open circuit, then go to the next step.
9	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].)
9		No	Go to the next step.
10	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].)
10		No	DTC troubleshooting completed.