DTC P0037:00 [SKYACTIV-G 2.0, SKYACTIV-G 2.5]

DTC P0037:00	HO2S heater control circuit low input
DETECTION CONDITION	• The PCM monitors the HO2S heater output voltage. If the PCM turns the HO2S heater off but the HO2S heater circuit remains low voltage, 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 check engine light 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)/Snapshot data is available. • DTC is stored in the PCM memory.
FAIL-SAFE FUNCTION	• Stops fuel feedback control
POSSIBLE CAUSE	• HO2S connector or terminals malfunction • Short to ground or open circuit in HO2S heater power supply circuit ― Short to ground in wiring harness between ENGINE1 15 A fuse and HO2S terminal C ― ENGINE1 15 A fuse malfunction ― Open circuit in wiring harness between main relay terminal C and HO2S terminal C • PCM connector or terminals malfunction • Short to ground in wiring harness between HO2S terminal D and PCM terminal 2C • HO2S heater malfunction • Open circuit in wiring harness between HO2S terminal D and PCM terminal 2C • PCM malfunction

DTC P0037:00

HO2S heater control circuit low input

DETECTION CONDITION

• The PCM monitors the HO2S heater output voltage. If the PCM turns the HO2S heater off but the HO2S heater circuit remains low voltage, 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 check engine light 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)/Snapshot data is available.

• DTC is stored in the PCM memory.

FAIL-SAFE FUNCTION

• Stops fuel feedback control

POSSIBLE CAUSE

• HO2S connector or terminals malfunction

• Short to ground or open circuit in HO2S heater power supply circuit

― Short to ground in wiring harness between ENGINE1 15 A fuse and HO2S terminal C

― ENGINE1 15 A fuse malfunction

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

• PCM connector or terminals malfunction

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

• HO2S heater malfunction

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

• PCM malfunction

STEP	INSPECTION	ACTION
1	VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED • Have the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor heater, HO2S heater related) been recorded?	Yes	Go to the next step.
No	Record the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS on the 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.
No	Go to the next step.
3	INSPECT HO2S CONNECTOR CONDITION • Switch the ignition off. • Disconnect the HO2S connector. • Inspect for poor connection (such as damaged/pulled-out pins, corrosion). • Is there any malfunction?	Yes	Repair or replace the connector and/or terminals, then go to Step 9.
No	Go to the next step.
4	INSPECT HO2S HEATER POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT • Verify that the HO2S connector is disconnected. • Switch the ignition ON (engine off). • Measure the voltage at the HO2S terminal C (wiring harness-side). • Is the voltage B+?	Yes	Go to the next step.
No	Inspect the ENGINE1 15 A fuse. • If the fuse is blown: ― Repair or replace the wiring harness for a possible short to ground. ― Replace the fuse. • If the fuse is deteriorated: ― 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 PCM CONNECTOR CONDITION • Switch the ignition off. • Disconnect the PCM connector. • Inspect for poor connection (such as damaged/pulled-out pins, corrosion). • Is there any malfunction?	Yes	Repair or replace the connector and/or terminals, then go to Step 9.
No	Go to the next step.
6	INSPECT HO2S HEATER CONTROL CIRCUIT FOR SHORT TO GROUND • Verify that the 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.
No	Go to the next step.
7	INSPECT HO2S HEATER • Inspect the HO2S heater. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) • Is there any malfunction?	Yes	Replace the HO2S, then go to Step 9. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
No	Go to the next step.
8	INSPECT HO2S HEATER CONTROL CIRCUIT FOR OPEN CIRCUIT • Verify that the HO2S and PCM connectors are disconnected. • Inspect for continuity between HO2S terminal D (wiring harness-side) and PCM terminal 2C (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 DTC TROUBLESHOOTING COMPLETED • Always reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) • Perform the KOER self test. (See KOEO/KOER SELF TEST [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) • Is the PENDING CODE for this DTC present?	Yes	Repeat the inspection from Step 1. • If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) Go to the next step.
No	Go to the next step.
10	VERIFY AFTER REPAIR PROCEDURE • Perform the “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
No	DTC troubleshooting completed.

STEP

INSPECTION

ACTION

VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED

• Have the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor heater, HO2S heater related) been recorded?

Yes

Go to the next step.

Record the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.

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.

Go to the next step.

INSPECT HO2S CONNECTOR CONDITION

• Switch the ignition off.

• Disconnect the HO2S connector.

• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).

• Is there any malfunction?

Yes

Repair or replace the connector and/or terminals, then go to Step 9.

Go to the next step.

INSPECT HO2S HEATER POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT

• Verify that the HO2S connector is disconnected.

• Switch the ignition ON (engine off).

• Measure the voltage at the HO2S terminal C (wiring harness-side).

• Is the voltage B+?

Yes

Go to the next step.

Inspect the ENGINE1 15 A fuse.

• If the fuse is blown:

― Repair or replace the wiring harness for a possible short to ground.

― Replace the fuse.

• If the fuse is deteriorated:

― Replace the fuse.

• If the fuse is normal:

― Repair or replace the wiring harness for a possible open circuit.

Go to Step 9.

INSPECT PCM CONNECTOR CONDITION

• Switch the ignition off.

• Disconnect the PCM connector.

• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).

• Is there any malfunction?

Yes

Repair or replace the connector and/or terminals, then go to Step 9.

Go to the next step.

INSPECT HO2S HEATER CONTROL CIRCUIT FOR SHORT TO GROUND

• Verify that the 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.

Go to the next step.

INSPECT HO2S HEATER

• Inspect the HO2S heater.

(See HEATED OXYGEN SENSOR (HO2S) INSPECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)

• Is there any malfunction?

Yes

Replace the HO2S, then go to Step 9.

(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)

Go to the next step.

INSPECT HO2S HEATER CONTROL CIRCUIT FOR OPEN CIRCUIT

• Verify that the HO2S and PCM connectors are disconnected.

• Inspect for continuity between HO2S terminal D (wiring harness-side) and PCM terminal 2C (wiring harness-side).

• Is there continuity?

Yes

Go to the next step.

Repair or replace the wiring harness for a possible open circuit, then go to the next step.

VERIFY DTC TROUBLESHOOTING COMPLETED

• Always reconnect all disconnected connectors.

• Clear the DTC from the PCM memory using the M-MDS.

(See AFTER REPAIR PROCEDURE [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)

• Perform the KOER self test.

(See KOEO/KOER SELF TEST [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)

• Is the PENDING CODE for this DTC present?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the PCM.

(See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)

Go to the next step.

VERIFY AFTER REPAIR PROCEDURE

• Perform the “AFTER REPAIR PROCEDURE”.

(See AFTER REPAIR PROCEDURE [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)

DTC troubleshooting completed.