Code No. P0136: Oxygen Sensor (Rear) System <SOHC>

OPERATION

The sensor signal is inputted to the engine-A/T-ECU (terminal No. 73) from the oxygen sensor (rear) output terminal (terminal No. 4).

The oxygen sensor (rear) (terminal No. 3) is earthed with engine-A/T-ECU (terminal No. 57).

function

The oxygen sensor (rear) converts the concentration of oxygen in the exhaust emission into a voltage signal and inputs the voltage signal to the engine-A/T-ECU.

When the air-fuel ratio is richer than the theoretical air-fuel ratio, the oxygen sensor (rear) outputs a voltage of about 1 V. When it is leaner than the theoretical air-fuel ratio, it outputs a voltage of about 0 V.

In response to the signal, the engine-A/T-ECU controls the fuel infection amount so that the air-fuel ratio can be equivalent to the theoretical air-fuel ratio.

TROUBLE JUDGMENT

Check Condition

After 3 or more minutes from when the engine has started up.

Engine coolant temperature approximately 80 °C or more.

Volumetric efficiency 25% or more.

Engine speed of 1,200 r/min or more.

Judgment Criterion

When the oxygen sensor output voltage is 0.2 V or less, and a power voltage of 5 V is applied to the oxygen sensor in the engine-A/T-ECU, the sensor output voltage is 4.5 V or more.

PROBABLE CAUSE

Failed oxygen sensor

Open/short circuit in oxygen sensor (rear) circuit or loose connector contact

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-II/III data list

Refer to Data list reference table .

Item 59: Oxygen sensor (rear)

Q: Is the check result normal?

YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points

).
NO: Go to Step 2

STEP 2. Connector check: C-31 oxygen sensor (rear) connector

Q: Is the check result normal?

YES: Go to Step 3

.
NO: Repair.

STEP 3. Perform voltage measurement at C-31 oxygen sensor (rear) connector.

Disconnect connector, and measure at harness side.

Resistance between terminal No. 3 and earth.

OK: 2 Ω or less

Q: Is the check result normal?

YES: Go to Step 7

.
NO: Go to Step 4

STEP 4. Connector check: C-111 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 5

.
NO: Repair.

STEP 5. Check harness between C-31 (terminal No. 3) oxygen sensor (rear) connector and C-111 (terminal No. 57) engine-A/T-ECU connector.

Check earthing line for open circuit and damage.

Q: Is the check result normal?

YES: Go to Step 6

.
NO: Repair.

STEP 6. MUT-II/III data list

Refer to Data list reference table .

Item 59: Oxygen sensor (rear)

Q: Is the check result normal?

YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points

).
NO: Replace engine-A/T-ECU.

STEP 7. Perform voltage measurement at C-31 oxygen sensor (rear) connector.

Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.

Engine: After warm-up

Ignition switch: ON

Voltage between terminal No. 3 and earth.

OK: 0.5 V or less

Q: Is the check result normal?

YES: Go to Step 9

.
NO: Go to Step 8

STEP 8. Connector check: C-111 engine-A/T-ECU connector

Q: Is the check result normal?

YES:

Check and repair harness between C-31 (terminal No. 3) oxygen sensor connector and C-111 (terminal No. 57) engine-A/T-ECU connector.

Check earthing line for damage.

NO: Repair.

STEP 9. Perform voltage measurement at C-31 oxygen sensor (rear) connector.

Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.

Engine: After warm-up

Voltage between terminal No. 4 and earth.

OK:

600 - 1,000 mV when 200 mV or lower abrupt racing is done a few seconds after abrupt deceleration from 4,000 r/min.

Q: Is the check result normal?

YES: Go to Step 12

.
NO: Go to Step 10

STEP 10. Check oxygen sensor (rear) itself

Check oxygen sensor (rear) itself (Refer to ).

Q: Is the check result normal?

YES: Go to Step 11

.
NO: Replace oxygen (rear) sensor.

STEP 11. Connector check: C-110 engine-A/T-ECU connector

Q: Is the check result normal?

YES:

Check and repair harness between C-31 (terminal No. 4) oxygen sensor connector and C-110 (terminal No. 73) engine-A/T-ECU connector.

Check output line for damage.

NO: Repair.

STEP 12. Perform voltage measurement at C-110 engine-A/T-ECU connector.

Measure engine-A/T-ECU terminal voltage.

Selector lever position: P

Engine: After warm-up

Voltage between terminal No. 73 and earth.

OK:

600 - 1,000 mV when 200 mV or lower abrupt racing is done a few seconds after abrupt deceleration from 4,000 r/min.

Q: Is the check result normal?

YES: Go to Step 14

.
NO: Go to Step 13

STEP 13. Connector check: C-110 engine-A/T-ECU connector

Q: Is the check result normal?

YES:

Check and repair harness between C-31 (terminal No. 4) oxygen sensor (rear) connector and C-110 (terminal No. 73) engine-A/T-ECU connector.

Check output line for open circuit.

NO: Repair.

STEP 14. Connector check: C-110 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 6

.
NO: Repair.


Code No. P0136: Oxygen Sensor (Rear) System <SOHC>

OPERATION The sensor signal is inputted to the engine-A/T-ECU (terminal No. 73) from the oxygen sensor (rear) output terminal (terminal No. 4). The oxygen sensor (rear) (terminal No. 3) is earthed with engine-A/T-ECU (terminal No. 57).
function The oxygen sensor (rear) converts the concentration of oxygen in the exhaust emission into a voltage signal and inputs the voltage signal to the engine-A/T-ECU. When the air-fuel ratio is richer than the theoretical air-fuel ratio, the oxygen sensor (rear) outputs a voltage of about 1 V. When it is leaner than the theoretical air-fuel ratio, it outputs a voltage of about 0 V. In response to the signal, the engine-A/T-ECU controls the fuel infection amount so that the air-fuel ratio can be equivalent to the theoretical air-fuel ratio.
TROUBLE JUDGMENT Check Condition After 3 or more minutes from when the engine has started up. Engine coolant temperature approximately 80 °C or more. Volumetric efficiency 25% or more. Engine speed of 1,200 r/min or more. Judgment Criterion When the oxygen sensor output voltage is 0.2 V or less, and a power voltage of 5 V is applied to the oxygen sensor in the engine-A/T-ECU, the sensor output voltage is 4.5 V or more.
PROBABLE CAUSE Failed oxygen sensor Open/short circuit in oxygen sensor (rear) circuit or loose connector contact Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. MUT-II/III data list Refer to Data list reference table . Item 59: Oxygen sensor (rear) Q: Is the check result normal? YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ). NO: Go to Step 2 .
	STEP 2. Connector check: C-31 oxygen sensor (rear) connector
	Q: Is the check result normal? YES: Go to Step 3 . NO: Repair.
	STEP 3. Perform voltage measurement at C-31 oxygen sensor (rear) connector.
	Disconnect connector, and measure at harness side. Resistance between terminal No. 3 and earth. OK: 2 Ω or less Q: Is the check result normal? YES: Go to Step 7 . NO: Go to Step 4 .
	STEP 4. Connector check: C-111 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 5 . NO: Repair.
	STEP 5. Check harness between C-31 (terminal No. 3) oxygen sensor (rear) connector and C-111 (terminal No. 57) engine-A/T-ECU connector.
	Check earthing line for open circuit and damage. Q: Is the check result normal? YES: Go to Step 6 . NO: Repair.
	STEP 6. MUT-II/III data list Refer to Data list reference table . Item 59: Oxygen sensor (rear) Q: Is the check result normal? YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ). NO: Replace engine-A/T-ECU.
	STEP 7. Perform voltage measurement at C-31 oxygen sensor (rear) connector.
	Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness. Engine: After warm-up Ignition switch: ON Voltage between terminal No. 3 and earth. OK: 0.5 V or less Q: Is the check result normal? YES: Go to Step 9 . NO: Go to Step 8 .
	STEP 8. Connector check: C-111 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Check and repair harness between C-31 (terminal No. 3) oxygen sensor connector and C-111 (terminal No. 57) engine-A/T-ECU connector. Check earthing line for damage. NO: Repair.
	STEP 9. Perform voltage measurement at C-31 oxygen sensor (rear) connector.
	Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness. Engine: After warm-up Voltage between terminal No. 4 and earth. OK: 600 - 1,000 mV when 200 mV or lower abrupt racing is done a few seconds after abrupt deceleration from 4,000 r/min. Q: Is the check result normal? YES: Go to Step 12 . NO: Go to Step 10 .
	STEP 10. Check oxygen sensor (rear) itself Check oxygen sensor (rear) itself (Refer to ). Q: Is the check result normal? YES: Go to Step 11 . NO: Replace oxygen (rear) sensor.
	STEP 11. Connector check: C-110 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Check and repair harness between C-31 (terminal No. 4) oxygen sensor connector and C-110 (terminal No. 73) engine-A/T-ECU connector. Check output line for damage. NO: Repair.
	STEP 12. Perform voltage measurement at C-110 engine-A/T-ECU connector.
	Measure engine-A/T-ECU terminal voltage. Selector lever position: P Engine: After warm-up Voltage between terminal No. 73 and earth. OK: 600 - 1,000 mV when 200 mV or lower abrupt racing is done a few seconds after abrupt deceleration from 4,000 r/min. Q: Is the check result normal? YES: Go to Step 14 . NO: Go to Step 13 .
	STEP 13. Connector check: C-110 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Check and repair harness between C-31 (terminal No. 4) oxygen sensor (rear) connector and C-110 (terminal No. 73) engine-A/T-ECU connector. Check output line for open circuit. NO: Repair.
	STEP 14. Connector check: C-110 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 6 . NO: Repair.