Page 545 - Foton Workshop Manual - Tunland (AT)

DIAGNOSTICS - ENGINE CONTROL SYSTEM 04-399

IN PTO OR CRUISE CONTROL MODE, ENGINE IS UNSTABLE

IDLE

Fault phenomenon Diagnosis logic Possible reasons

• Fuel pipe • Injector fault
• Fuel system • Fuel pipe fault 04
• Accelerator pedal • Fuel system fault
In PTO or cruise control • Turbocharger • Accelerator pedal fault
mode, engine is unstable idle.
• Gearbox • Turbocharger fault
• Injector • Gearbox fault
• ECM • ECM fault

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 fuel system
(a) Check whether fuel filter is blocked.
(b) Check whether pipe of the fuel system leaks.

Is the inspection result normal?
YES>To step 3.
No >Maintenance related faults.

3 . Check the accelerator pedal and its wire harness
(a) Check whether the accelerator pedal is damaged or stuck.
(b) Check whether the harness of the accelerator pedal is damaged.
Is the inspection result normal?

YES>To step 4.
No >Maintenance related faults.

4 . Check the fuel injector

(a) Unplug the injector connector.
(b) Remove the fuel distribution pipes and injector outside the engine together.
(c) Add the battery voltage of 12 V directly to the injector.

Page 545