DTC P0141 [YF (2.0L Zetec)]


DTC P0141	HO2S (Rear) heater circuit
DETECTION CONDITION	• The PCM checks HO2S-12 heater circuit for open/shorts and excessive current draw. If the current draw exceeds a calibrated limit and/or open or short is detected, the PCM determines the HO2S-12 heater circuit is malfunction.
POSSIBLE CAUSE	• Short to power supply circuit in harness or HO2S-12 heater • Water in harness connector • Open circuit in wiring between HO2S-12 terminal 1 and main relay terminal 87 • Open circuit in wiring between HO2S-12 terminal 2 and PCM terminal 100 • Low battery voltage • Corrosion or poor mating terminals and wiring • Damaged HO2S-12 heater • Damaged PCM


STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2	VERIFY REPAIR INFORMATION AVAILABILITY • Verify related service repair information availability. • Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	INDETIFY TRIGGER DTC FOR FREEZE FRAME DATA • Is DTC P0141 on FREEZE FRAME DATA?	Yes	Go to the next step.
3		No	Go to FREEZE FRAME DATA DTC inspection. (See DTC TABLE [YF (2.0L Zetec)].)
4	CHECK FOR HO2S-12 HARNESS CONNECTOR Note • Refer to the PCM connector pin number in the beginning of this pinpoint test. • Visually inspect the HO2S-12 circuit for exposed wiring, water contamination, corrosion and proper assembly. • Were any concerns found during inspection?	Yes	Repair any concerns found during inspection, then go to Step 11.
4		No	Go to the next step.
5	PERFORM KEY ON ENGINE OFF (KOEO) SELF TEST • Connect the WDS or equivalent to DLC-2. • Turn the ignition switch to ON. • Perform KOEO self test. • Is DTCs P0135 or P0141 present?	Yes	Go to the next step.
5		No	Intermittent malfunction exist, go to the Step 11.
6	CHECK VPWR VOLTAGE TO HO2S-12 HARNESS VONNECTOR Note • If DTCs P0141 and P0135 are displayed, both heater circuits will require testing. DTCs displayed separately are to be test individually. • Disconnect HO2S-12 connector. • Turn the ignition switch to ON. • Measure voltage between terminal 1 and 3 at HO2S-12 harness side connector. • Is the voltage greater than 10.5 V?	Yes	Go to the next step.
6		No	Inspect fuse in VPWR circuit. If fuse is normal repair open circuit. Then go to Step 11.
7	CHECK HO2S-12 HEATER CIRCUIT FOR SHORT TO VPWR AND GND • Disconnect PCM. • Measure resistance between following PCM harness side connector terminals: - Between terminal 100 and 24, 51, 76, 103 - Between terminal 100 and 91 - Between terminal 100 and 71, 97 • Is each resistance greater than 10,000 ohms?	Yes	Go to the next step.
7		No	Repair short to VPWR or GND circuit, then go to Step 11.
8	CHECK HO2S HEATER CIRCUIT FOR OPEN IN HARNESS • Measure resistance at harness side connectors between HO2S-12 terminal 1 and PCM terminal 100 • Is resistance less than 5.0 ohms?	Yes	Go to the next step.
8		No	Repair for open or excessive resistance in the HO2S-12 heater circuit in harness, then go to Step 11.
9	CHECK HO2S-12 HEATER RESISITANCE • Measure resistance at HO2S-12 component side connector between 1 and 2. • Is resistance 3-30 ohms?	Yes	Go to the next step.
9		No	Replace HO2S-12, then go to Step 11.
10	CHECK HO2S CASE FOR SHORT TO VPWR, HEATER CONTROL AND SIGNAL RETURN • Measure resistance for following: • Between HO2S-12 component side connector terminal 2 and HO2S-12 case • Between terminal 2 and 3 at HO2S-12 component side connector. • Between HO2S component side connector terminal 1 and HO2S-12 case • Is the resistance greater than 10,000 ohms?	Yes	Replace PCM, then go to the next step.
10		No	Replace HO2S-12, then go to the next step.
11	VERIFY TROUBLESHOOTING OF DTC P0141 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the WDS or equivalent. • Perform KOEO/KOER self test. (See KOEO/KOER SELF-TEST [YF (2.0L Zetec)].) • Is the PENDING CODE same DTC present?	Yes	Replace PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [YF (2.0L Zetec)].)
11		No	Go to the next step.
12	VERIFY AFTER REPAIR PROCEDURE • Perform "After Repair Procedure". (See AFTER REPAIR PROCEDURE [YF (2.0L Zetec)].) • Is there any DTC present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [YF (2.0L Zetec)].)
12		No	Troubleshooting completed.