Geely Emgrand X7. Manual part — 212

DTC P0420

Yes

DTC code other than P0420

No

2

Start engine and turn on the fault diagnosis tester.

3

Keep the engine speed at 2,500 rpm for more than 2 min to warm up the engine, until
the engine coolant temperature reaches 80 (176 ?F).

℃

4

(d) Select on the fault diagnosis tester: Engine/Read Data Flow/Group 1 Oxygen
Sensor Voltage 1 (Front Oxygen Sensor).

Group 1 Oxygen Sensor Voltage 2 (Rear oxygen sensor)

GC02-0330b

0V

0V

0V

0V

1V

1V

1V

1V

Whether front oxygen sensor and rear oxygen sensor signal voltage is matching Normal TWC in

5

Observe front oxygen sensor and rear oxygen sensor output voltages.

Next

Next

No

Refer to 2.2.7.14 DTC Chapter Index.

Yes

Normal TWC

Front oxygen

sensor

Rear oxygen

sensor

Deteriorated TWC

847

the figure?

Serious Warning: Propane gas is flammable gas. It is strictly prohibited to operate propane
gas near a fire, otherwise it will cause a fire.

6

Carry out the oxygen sensor signal test.

A. If the voltage data is consistently lower than 0.45 V (mixture too thin), carry out the

following inspection steps:

z Spray proper amount of propane gas into the intake.

z Inspect whether the sensor voltage data is changed significantly, as the signal voltage will
increase rapidly.

Front Oxygen Sensor Signal
Voltage

Rear Oxygen Sensor Signal
Voltage

To Step

Obvious Change

No Change

A

No Change

Obvious Change

B

Obvious Change

No Change

C

No Change

No Change

D

7

Inspect whether there is exhaust leakage.

Yes

Repair the faulty part. Go to step 11

No

B

Inspect the cause for engine
air-fuel ratio too lean/too rich.
Refer to 2.2.7.4 Fault Symptom
Table.

A

C

D

Refer to 2.4.7.2 “Replacement of
Front Oxygen Sensor” to replace
the front oxygen sensor. Go to
Step 11.

Go to step 9

Yes

Refer to 2.2.7.3 Intermittent Fault
Inspection for intermittent fault.

No

848

11

Use a fault diagnosis tester to confirm whether the DTC Code is stored again.

A. Connect fault diagnosis tester to the data link connector.

B. Rotated 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 5min.

E. Road test the vehicle for at least 10min.

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

12 Troubleshooting

8

Refer to 2.7.6.3 “Replacement of Three-way Catalytic Converter” to replace the
three-way catalytic converter.

9

Inspect whether there is exhaust leakage.

10

Replace the rear oxygen sensor. Refer to 2.4.6.1 Replacement of Rear Oxygen Sensor.

No

Refer to 2.2.7.3 Intermittent Fault
Inspection for intermittent fault.

Yes

Next

Yes

Repair the faulty part. Go to step 11

No

Next

Go to step 11

849

2.12.7.39 DTC P0458 P0459

1. DTC

description:

DTC P0458

Canister Control Valve Circuit Short To Low Voltage or Open

DTC P0459

Canister Control Valve Circuit Short To High Voltage

EVAP solenoid valve absorbs fuel vapor from the evaporative emission canister to the intake
manifold. EVAP solenoid valve is controlled by the pulse width modulation (PWM). The circuit
consists of:

● Operating Voltage: Battery voltage passes through ECM controlled main relay terminal No.3

to reach EVAP solenoid harness connector EN24 terminal A.

● ECM control circuit: EVAP electromagnetic valve wire harness connector EN24 terminal B

and ECM wire harness connector EN01 terminal 64 are connected. ECM has an internal
driver circuit to control the solenoid valve ground. Drive circuit is equipped with a feedback
circuit to ECM. ECM monitors the feedback voltage control circuit to determine whether the
control circuit is open, short to ground or short to voltage.

2. Conditions For Setting DTC and The Fault Location:

DTC Code

DTC Detection
Strategy

Conditions For Setting The DTC
(Control Strategy)

Fault Locations

P0458

Hardware Circuit
Inspection

At idle conditions, when canister
solenoid valve is inoperative, make
canister solenoid valve circuit short to
ground or open, DTC code set.

P0459

Hardware Circuit
Inspection

At idle conditions, when the canister
solenoid valve is inoperative, make
anister solenoid valve circuit short to
power supply, DTC code set.

1. Canister

Solenoid Valve
Circuit

2. Solenoid

Valve

3. ECM

850