Geely Emgrand X7. Manual part — 195

2.12.7.25 DTC P0141

1. DTC

description:

DTC P0141

Rear Oxygen Sensor Heater Inoperation

The post-catalytic heated oxygen sensor (HO2S) is used for monitoring three-way catalytic
converter working status. The sensor compares the oxygen content in ambient air and oxygen
content in the exhaust flow. Each heated oxygen sensor has an internal heating element for sensor
heating. ECM controls the heated oxygen sensor heating control circuit. This makes the system
enter into the closed-loop control mode earlier, so that ECM can calculate Air-fuel ratio earlier.
ECM controls the heating control circuit switched on or off, so that heated type oxygen sensor
working temperature maintains in the specified range. Engine control module detects the
temperature by Measure the heater current.

The rear oxygen sensor heating coil voltage is provided by The Main Relay, which is controlled by
ECM. When the ignition switch is turned to "ON" position, the rear oxygen sensor harness
connector EN03 terminal No.D voltage is provided by the battery. ECM controls the heater
working hours by ECM harness connector EN01 terminal No.23.

2. Conditions For Setting DTC and The Fault Location:

DTC Code

DTC Detection
Strategy

Conditions For Setting The
DTC (Control Strategy)

Fault Locations

P0135

Hardware Circuit
Inspection

1. Engine Running Longer

than 60 s.

2. At idle Running Condition.

3. Pre-Catalytic

Oxygen

Sensor Heating

4. Pre-Catalytic

Oxygen

Sensor Heating Control
Terminal Disconnected.

5. Duration Less Than 20s.

1. Sensor

Circuit

2. Sensor

3. ECM.

3. Circuit

sketch

Refer to2.12.7.24 DTC P0137 P0138 P0140.

4. Diagnostic

Steps:

Note: Before carrying out this diagnosis step, observe the data list on fault diagnosis tester and
analyze the accuracy of the data, as these will help with quick diagnosis.

Step 1

Initial Inspection

Inspect the existence of following factors that will affect the heated type oxygen sensor working
status:

(a) Exhaust system leakage or blockage.

(b) Water enters into the heated oxygen sensor connector.

(c) After engine working in high temperature, whether exhaust pipes are too hot or not.

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Step 2

Inspect the rear oxygen sensor heater resistance.

(a) Rotated ignition switch to OFF position .

(b) Disconnect the rear oxygen sensor wiring harness connector.

(c) Measure the rear oxygen sensor heater resistance.

Standard Resistance

Connectors C and D, 8.1-11.1 Ω @ 20°C(68 ?F)

(d) Connect the rear oxygen sensor wiring harness connector.

Is resistance the specified value?

Step 3

Inspect the terminal No.D to ground voltage.

(a) Rotated ignition switch to OFF

position .

(b) Disconnect the rear oxygen

sensor wiring harness connector.

(c) Rotated ignition switch to ON

position .

(d)

Measure voltage between
Post-Catalytic oxygen sensor
harness connector EN03 terminal
D and ground.

Standard Voltage: 11-14V

(e) Connect the rear oxygen sensor

harness connector EN03.

NL02-2069b

A

B

C

D

EN03 后氧传感器线束连接器

D

Is voltage the specified value?

Step 4

Inspect the rear oxygen sensor heater control terminal continuity.

No

The rear oxygen sensor heater power supply circuit
malfunction.

Yes

No

Replace the rear oxygen sensor. Refer to 2.4.7.1
Replacement of Rear Oxygen Sensor.

Yes

Next

EN03 rear oxygen sensor harness connector

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(a) Rotated ignition switch to OFF position .

(b) Disconnect the rear oxygen sensor harness connector EN03.

(c) Disconnect ECM harness connector EN01.

(d) Test Continuity between rear

oxygen sensor wiring harness
connector EN03 terminal C and
ECM harness connector EN01
terminal No.23.

Standard Resistance: Less than 1 Ω

(e) Connect ECM harness connector

EN01.

(f) Connect the rear oxygen sensor

wiring harness connector EN03.

NL02-2070b

A

B

C

D

EN03 后氧传感器线束连接器

C

Is resistance the specified value?

Step 5

Inspect ECM working circuit.

(a) Inspect whether ECM power supply circuit is normal.

(b) Inspect whether ECM ground circuit is normal.

(a) Replace

ECM.

(b) Carry out the crankshaft position sensor learning, refer to 2.12.7.11 “Crankshaft Position

Sensor (CKP) Learning.

Step 7

Use fault diagnosis tester to confirm if DTC is stored again .

(a) Connect the fault diagnosis tester to the diagnostic interface.

(b) Turn ignition switch to ON position.

Step 6

Replace ECM. Refer to 2.12.8.1 Replacement of Engine Control Module.

Next

No

Repair the faulty part.

Yes

No

ECM control circuit malfunction.

Yes

EN03 rear oxygen sensor harness connector

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(c) Clear DTC code.

(d) Start and run the engine at idle speed to warm up the engine for at least 5 min.

(e) test the vehicle on the road for at least 5min.

(f) Read control system DTC code again to confirm that the system has no DTC code.

5. Maintenance

guide

:

Refer to 2.4.6.1 “Replacement of Rear Oxygen Sensor” to replace the rear oxygen sensor.

Step 8

Troubleshooting

No

Refer to 2.12.7.3 Intermittent Fault
Inspection for intermittent fault.

Yes

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