Page 629 - Foton Workshop Manual - Tunland (AT)

DIAGNOSTICS - ENGINE CONTROL SYSTEM 04-483

THE VACUUM PUMP DOES NOT KEEP ENOUGH VACUUM

Fault phenomenon Diagnosis logic Possible reasons
• Vacuum system • Vacuum system fault
The vacuum pump does not • Vacuum pump • Vacuum pump fault
keep enough vacuum
• Vacuum booster • Vacuum booster fault 04

Diagnosis Procedure

1 . Check the engine data
(a) Ignition switch: OFF.
(b) Connect the diagnosis tool with the fault diagnosis connector (16 pins) on the lower
left of the dashboard.
(c) Ignition switch: ON, and start the diagnostic tool.
(d) Read the motor data shown on the diagnostic tool.

Check whether the data flow is normal or not.
YES>To step 2.

No >Maintenance related faults.

2 . Check vacuum pump
(a) Check whether vacuum pump is damaged or not.

Is the inspection result normal?
YES>To step 3.
NO>Replace the vacuum pump.

3 . Check vacuum booster
(a) Check whether the vacuum booster leaks.
Is the inspection result normal?

YES>To step 4.
NO>Replace the vacuum booster.

4 . Check vacuum system
(a) Check whether the vacuum system leaks.
(b) Check whether the vacuum pipeline has phenomenon of aging, cracking and so on.
Is the inspection result normal?

YES>Complete the diagnosis and the system is confirmed to be normal.
No >Maintenance related faults.

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