Lifan 620. Manual — part 9

difference between the inlet and outlet hole. When no electric pulse is produced, the canister
control valve will be closed. According to the signals from each sensor, the ECU can control the
time for power connection of the canister solenoid valve, and then control the volume of the
cleaning air flow.

(3) Trouble diagnosis:

The ECU will carry out trouble diagnosis for the driving stage of the

canister control valve. When the driving stage of the canister control valve is short or overloaded to
the battery voltage, as well as short and open to the ground, the fuel ration closed loop control
self-learning and the idle speed air ration self-learning will be closed, while the self-leaning data at
that moment will be effective. When the canister solenoid valve is under trouble, the engine is
likely to experience unstable idle speed or over-high idle speed.

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Section III Steps for Trouble Diagnosis with DTC

I LF Self-developed Engine

(LF481Q3)

1. A/C evaporator outlet temperature sensor

(see Table 1-3)

Table 1-3

Diagnostic Trouble Code (DTC)

Trouble Location or Type

P1535

A/C evaporator temperature circuit high input---short or open to power supply

1

2

3

4

1

2

3

multimeter. Is the resistance between 1.6k and 2.4k?

No Replace

sensor

Yes Replace

sensor

4

Slowly turn the throttle position sensor from one side to

the other side. Check for open or short circuit or a jump

resistance between pin (1) (-) and pin (3) (+) with a

multimeter.

No

Replace ECU

5

Connect an adapter between the ECU and the harness.

Check for open or short circuit between pin J1-20, J1-05,

J1-24 of the ECU and the pin (1), (2), (3) of the sensor

with a multimeter.

Yes

Repair or replace harness

38

3. Shock sensor

(see Table 1-5)

Table 1-5

Diagnostic Trouble Code (DTC)

Trouble Location or Type

P0325

Shock sensor 1 circuit trouble

S/N Operation Test

Results

Actions

1

Turn off the ignition switch, and stop the engine.

Next step

Yes Next

step

2

Disconnect the shock sensor from the harness.

Measure the resistance between pin (1) and pin (2)

No Renew

sensor

3

4

5

1

2

3

of the sensor with a multimeter.

4

Turn on the ignition switch, and do not start the

engine.

Next

step

Yes Replace

ECU

5

In neutral position, start the engine, and keep idle

speed. Step on the accelerator. Through the adapter,

measure the voltage between pin (4) and pin (1) with

a multimeter, namely between pin J1-42 and pin J1-21

of the ECU. Does the voltage gradually increase to

4V?

No

Replace ECU

Replace sensor

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5. Oxygen sensor

(see Table 1-7)

Table 1-7

Diagnostic Trouble Code (DTC)

Trouble Location or Type

P0031

Heated oxygen sensor heater control circuit low (front)

P0032

Heated oxygen sensor heater control circuit high (front)

P0037

Heated oxygen sensor heater control circuit low (rear)

P0038

Heated oxygen sensor heater control circuit high (rear)

P0130

Oxygen sensor circuit trouble (front)

1

2

3

4

5

6

reaches normal temperatue.

Yes Next

step

7

Disconnect the oxygen sensor from the harness.

Measure the voltage between pin (4) (+) and pin (3)

(-) with a multimeter. Is the voltage between 0.1V and

0.9V?

No Replace

sensor

Yes

Repair or replace harness

8

Connect an adapter between the ECU and the

harness. Check for open or short circuit between pin

J1-06, pin J1-62 (front)/ J1-38 (rear) of the ECU and

pin (3), pin (4) of the sensor with a multimeter.

No Replace

ECU

40