Fault code: EMS 4389 SCANIA

Error identification:

The highest level to which the control unit can adjust the fuel volume for the cylinder has been reached.

Cause:

The cylinder output is lower than that of the other cylinders.

This may be caused by the following:

• Air in the fuel system caused, for example, by too low a fuel level or leaks in the fuel supply line. In this case fault codes will probably be generated for several cylinders.

• Internal or external leakage in the unit injector.

• HPI: Defective fuel supply or injection timing solenoid valve.

• PDE: Defective solenoid valve on the unit injector.

• Low compression in the cylinder.

Notes:

As a result, the engine runs unevenly.

If the cylinder receives too little fuel, this may result in white smoke.

Action:

Bleed the fuel system.

Make sure there are no leaks in the supply line.

If the fault recurs:

Check the unit injectors.

HPI: Check the fuel volume and injection timing solenoid valves.

PDE: Check the solenoid valve on the unit injector in question.

Check the cylinder compression by carrying out a compression test.

To verify that the fault has been rectified and that the fault code does not recur, you can click on fault code monitoring and look at the fault code. This fault code is not activated immediately. In order for the control unit to set an active fault code, the control unit must run a test for 4x15 minutes with negative results. You can use fault code monitoring to see whether the fault code is pending, i.e. the fault code is about to be generated.