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D

Pre-catalytic Oxygen Sensor Harness 
Connector EO02

ECM Harness Connector EO01

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect oxygen sensor wiring harness connector EO02.

(c)

Disconnect ECM harness connector EO01.

(d)

Measure resistance between pre-catalytic oxygen sensor
wiring harness connector EO02 terminal B and ECM harness
connector terminal No.10. Check whether the circuit is open.
otherwise, repair the faulty part.

(e)

Measure resistance between pre-catalytic oxygen sensor
wiring harness connector EO02 terminal B and a reliable
ground. Check whether the circuit is short to ground.
otherwise, repair the faulty part.

(f)

Measure voltage between pre-catalytic oxygen sensor wiring
harness connector EO02 terminal B and a reliable ground.
Check whether the circuit is short to power supply. Otherwise,
repair the faulty part.

Test Items

Standard Value

Resistance Between EO02 (B) and EO01
(10)

Less than 1 Ω

Resistance Between EO02 (B) and A
Reliable Ground

10 kΩ or higher

Voltage Between EO02 (B) and A Reliable
Ground

0 V

Normal

Go to step 15

Step 12

Check pre-catalytic oxygen sensor ground circuit..

Engine

Control System JL4G15-D

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FE02-5351b

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A

B

C

D

Pre-catalytic Oxygen Sensor Harness 
Connector EO02

ECM Harness Connector EO01

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect oxygen sensor wiring harness connector EO02.

(c)

Disconnect ECM harness connector EO01.

(d)

Measure resistance between pre-catalytic oxygen sensor
wiring harness connector EO02 terminal A and ECM harness
connector terminal No.2. Check whether the circuit is open.
otherwise, repair the faulty part.

(e)

Measure resistance between pre-catalytic oxygen sensor
wiring harness connector EO02 terminal A and a reliable
ground. Check whether the circuit is short to ground.
otherwise, repair the faulty part.

(f)

Measure voltage between pre-catalytic oxygen sensor wiring
harness connector EO02 terminal A and a reliable ground.
Check whether the circuit is short to power supply. otherwise,
repair the faulty part.

Test Items

Standard Value

Resistance Between EO02 (A) and EO01 (2)

Less than 1 Ω

Resistance Between EO02 (A) and A Reliable
Ground

10 kΩ or higher

Voltage Between EO02 (A) and A Reliable
Ground

0 V

Execute next step as per normal.

Next

Step 13

Check ECM power supply circuit.

(a)

Check whether ECM power supply circuit is normal.

(b)

Check whether ECM ground circuit is normal.

No

Repair the faulty part.

Yes

Step 14

Replace ECM.

(a)

Replace ECM. Refer to 

2.2.8.8

 

Engine Control Module

Replacement

.

(b)

Carry out crankshaft position sensor self learn. Refer to

2.12.7.11

 

Crankshaft Position Sensor (CKP) Learn

.

Next

Step 15

Use scan tool to confirm whether the DTC code is stored again.

(a)

Connect scan tool to the datalink connector.

(b)

Turn the ignition switch to "ON" position.

(c)

Clear DTC code.

(d)

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

(e)

Road test the vehicle for at least 10 min.

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Control System JL4G15-D

Engine

(f)

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

No

Intermittent Fault. Refer to 

2.2.7.3

 

Intermittent

Fault Check

Yes

Step 16

Diagnostic completed.

5. Repair Instructions:

Replace the pre-catalytic oxygen sensor. Refer to 

2.4.7.2

 

Pre-Catalytic Oxygen Sensor Replacement

.

2.12.7.23 DTC P0135

1. DTC Descriptor:

DTC

P0135

Pre-Catalytic Oxygen Sensor Heater Malfunction

Upstream Heated Oxygen Sensor (HO

2

S) is used for fuel control. 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. ECM controls the heated oxygen
sensor heating control circuit. This makes the system enter the closed-loop system earlier, so that ECM will calculate Air-Fuel ratio
earlier. ECM controls the heating control circuit switched on or off, so that heated oxygen sensor working temperature maintains in
the specified range. ECM measures the heater current to determine the temperature.

Pre-Catalytic oxygen sensor heating coil voltage is provided by The Main Relay controlled by ECM, when the ignition switch is turned
to "ON", EO02 sensor harness connector terminal D will have battery voltage. ECM controls heater working hours through ECM
harness connector EO01 terminal No.14.

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 Checks

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 20 s.

1. Sensor Circuit

2. Sensor

3. ECM

3. Schematic:

Refer to 

2.12.7.22

 

DTC P0131 P0132 P0133 P0134

.

4. Diagnostic Steps:

Note

Before carrying out this diagnosis step, observe the data list on scan tool and analyze the accuracy of the data, as
these will help with quick diagnosis.

Step 1

Initial Inspection

Engine

Control System JL4G15-D

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Check the existence of following factors that will affect the oxygen
sensor working status:

(a)

Exhaust system leakage or blockage.

(b)

Water entering the heated oxygen sensor connector.

(c)

Engine working at high temperatures, exhaust pipes too hot.

Next

Step 2

Check pre-catalytic oxygen sensor heater resistance.

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect oxygen sensor wiring harness connector.

(c)

Measure heater resistance between pre-catalytic oxygen
sensor terminals C and D.

Standard Resistance: 9 Ω/20°C (68 ºF)

(d)

Connect pre-catalytic oxygen sensor wiring harness
connector.

Is the resistance specified value?

No

Replace the pre-catalytic oxygen sensor.
Refer to 

2.4.7.2

 

Pre-Catalytic Oxygen Sensor

Replacement

Yes

Step 3

Check terminal D to ground voltage.

FE02-5352b

A

B

C

D

Pre-catalytic Oxygen Sensor Harness 
Connector EO02

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect oxygen sensor wiring harness connector.

(c)

Turn the ignition switch to "ON" position.

(d)

Measure voltage between Pre-Catalytic oxygen sensor
wiring harness connector EO02 terminal D and a reliable
ground.

Standard Voltage Value: 11-14 V

(e)

Connect the pre-catalytic oxygen sensor wiring harness
connector EO02.

Is the voltage specified value?

No

Pre-Catalytic oxygen sensor heater power
supply circuit fault

Yes

Step 4

Check pre-catalytic oxygen sensor heater control terminal continuity.

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