Code No. P0141: Cylinder 1, 4 Oxygen Sensor (Rear) Heater System <Vehicles for Hong kong>

OPERATION

Power is supplied to the heater power terminal (terminal No. 1) of the cylinder 1, 4 oxygen sensor (rear) connector from the engine control relay (terminal No. 1).

The heater (terminal No. 3) of the cylinder 1, 4 oxygen sensor (rear) connector is controlled by the power transistor in the engine-A/T-ECU (terminal No. 24).

FUNCTION

The power supply to the cylinder 1, 4 oxygen sensor (rear) heater is controlled by the ON/OFF control of the power transistor in the engine-A/T-ECU.

Heating the cylinder 1, 4 oxygen sensor (rear) heater enables the cylinder 1, 4 oxygen sensor (rear) to provide good response even when the exhaust emission temperature is low.

TROUBLE JUDGMENT

Check Conditions

60 seconds have elapsed since the previous monitoring started.

Engine coolant temperature is 20°C or higher.

While cylinder 1, 4 oxygen sensor (rear) heater is on.

Battery positive voltage is 11 - 16 V.

Judgment Criterion

Cylinder 1, 4 oxygen sensor (rear) heater currents have continued to be 0.16 A or lower, or 5.0 A or higher for 4 seconds.

PROBABLE CAUSE

Failed cylinder 1, 4 oxygen sensor (rear) heater

Open/short circuit in cylinder 1, 4 oxygen sensor (rear) circuit or loose connector contact

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-123 cylinder 1, 4 oxygen sensor (rear) connector

Q: Is the check result normal?

YES: Go to Step 2

.
NO: Repair.

STEP 2. Perform resistance measurement at B-123 cylinder 1, 4 oxygen sensor (rear) connector.

Disconnect connector, and measure at sensor side.

Resistance between terminal No. 1 and No. 3.

OK: 11 - 18 Ω

Q: Is the check result normal?

YES: Go to Step 3

.
NO: Replace cylinder 1, 4 oxygen sensor (rear).

STEP 3. Perform voltage measurement at B-123 cylinder 1, 4 oxygen sensor (rear) connector.

Disconnect connector, and measure at harness side.

Ignition switch: ON

Voltage between terminal No. 1 and earth.

OK: System voltage

Q: Is the check result normal?

YES: Go to Step 5

.
NO: Go to Step 4

STEP 4. Connector check: B-17X engine control relay connector

Q: Is the check result normal?

YES:

Check and repair harness between B-123 (terminal No. 1) cylinder 1, 4 oxygen sensor (rear) connector and B-17X (terminal No. 1) engine control relay connector.

Check power supply line for open/short circuit.

NO: Repair.

STEP 5. Perform voltage measurement at C-134 engine-A/T-ECU connector.

Measure engine-A/T-ECU terminal voltage.

Ignition switch: ON

Voltage between terminal No. 24 and earth.

OK: System voltage

Q: Is the check result normal?

YES: Go to Step 8

.
NO: Go to Step 6

STEP 6. Connector check: C-134 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 7

.
NO: Repair.

STEP 7. Check harness between B-123 (terminal No. 3) cylinder 1, 4 oxygen sensor (rear) connector and C-134 (terminal No. 24) engine-A/T-ECU connector.

Check earthing line for open/short circuit.

Q: Is the check result normal?

YES: Replace engine-A/T-ECU.
NO: Repair.

STEP 8. Connector check: C-134 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 9

.
NO: Repair.

STEP 9. Check harness between B-123 (terminal No. 1) cylinder 1, 4 oxygen sensor (rear) connector and B-17X (terminal No. 1) engine control relay connector.

Check power supply line for damage.

Q: Is the check result normal?

YES: Go to Step 10

.
NO: Repair.

STEP 10. Check harness between B-123 (terminal No. 3) cylinder 1, 4 oxygen sensor (rear) connector and C-134 (terminal No. 24) engine-A/T-ECU connector.

Check earthing line for damage.

Q: Is the check result normal?

YES: Go to Step 11

.
NO: Repair.

STEP 11. Check the trouble symptoms.

Q: Does trouble symptom persist?

YES: Replace engine-A/T-ECU.
NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points


Code No. P0141: Cylinder 1, 4 Oxygen Sensor (Rear) Heater System <Vehicles for Hong kong>

OPERATION Power is supplied to the heater power terminal (terminal No. 1) of the cylinder 1, 4 oxygen sensor (rear) connector from the engine control relay (terminal No. 1). The heater (terminal No. 3) of the cylinder 1, 4 oxygen sensor (rear) connector is controlled by the power transistor in the engine-A/T-ECU (terminal No. 24).
FUNCTION The power supply to the cylinder 1, 4 oxygen sensor (rear) heater is controlled by the ON/OFF control of the power transistor in the engine-A/T-ECU. Heating the cylinder 1, 4 oxygen sensor (rear) heater enables the cylinder 1, 4 oxygen sensor (rear) to provide good response even when the exhaust emission temperature is low.
TROUBLE JUDGMENT Check Conditions 60 seconds have elapsed since the previous monitoring started. Engine coolant temperature is 20°C or higher. While cylinder 1, 4 oxygen sensor (rear) heater is on. Battery positive voltage is 11 - 16 V. Judgment Criterion Cylinder 1, 4 oxygen sensor (rear) heater currents have continued to be 0.16 A or lower, or 5.0 A or higher for 4 seconds.
PROBABLE CAUSE Failed cylinder 1, 4 oxygen sensor (rear) heater Open/short circuit in cylinder 1, 4 oxygen sensor (rear) circuit or loose connector contact Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. Connector check: B-123 cylinder 1, 4 oxygen sensor (rear) connector
	Q: Is the check result normal? YES: Go to Step 2 . NO: Repair.
	STEP 2. Perform resistance measurement at B-123 cylinder 1, 4 oxygen sensor (rear) connector.
	Disconnect connector, and measure at sensor side. Resistance between terminal No. 1 and No. 3. OK: 11 - 18 Ω Q: Is the check result normal? YES: Go to Step 3 . NO: Replace cylinder 1, 4 oxygen sensor (rear).
	STEP 3. Perform voltage measurement at B-123 cylinder 1, 4 oxygen sensor (rear) connector.
	Disconnect connector, and measure at harness side. Ignition switch: ON Voltage between terminal No. 1 and earth. OK: System voltage Q: Is the check result normal? YES: Go to Step 5 . NO: Go to Step 4 .
	STEP 4. Connector check: B-17X engine control relay connector
	Q: Is the check result normal? YES: Check and repair harness between B-123 (terminal No. 1) cylinder 1, 4 oxygen sensor (rear) connector and B-17X (terminal No. 1) engine control relay connector. Check power supply line for open/short circuit. NO: Repair.
	STEP 5. Perform voltage measurement at C-134 engine-A/T-ECU connector.
	Measure engine-A/T-ECU terminal voltage. Ignition switch: ON Voltage between terminal No. 24 and earth. OK: System voltage Q: Is the check result normal? YES: Go to Step 8 . NO: Go to Step 6 .
	STEP 6. Connector check: C-134 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 7 . NO: Repair.
	STEP 7. Check harness between B-123 (terminal No. 3) cylinder 1, 4 oxygen sensor (rear) connector and C-134 (terminal No. 24) engine-A/T-ECU connector.
	Check earthing line for open/short circuit. Q: Is the check result normal? YES: Replace engine-A/T-ECU. NO: Repair.
	STEP 8. Connector check: C-134 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 9 . NO: Repair.
	STEP 9. Check harness between B-123 (terminal No. 1) cylinder 1, 4 oxygen sensor (rear) connector and B-17X (terminal No. 1) engine control relay connector.
	Check power supply line for damage. Q: Is the check result normal? YES: Go to Step 10 . NO: Repair.
	STEP 10. Check harness between B-123 (terminal No. 3) cylinder 1, 4 oxygen sensor (rear) connector and C-134 (terminal No. 24) engine-A/T-ECU connector.
	Check earthing line for damage. Q: Is the check result normal? YES: Go to Step 11 . NO: Repair.
	STEP 11. Check the trouble symptoms. Q: Does trouble symptom persist? YES: Replace engine-A/T-ECU. NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).