Diagnostic Function of Volvo Engine

Diagnostic Function of Volvo Engine

First start

The engine can be started after the installation is completed and checked. Each control unit supplied with the engine or as a spare part has a default setting. The default setting is chosen to allow the engines to work in most applications. In certain circumstances, the engine can run unevenly or behave in an undesirable manner. If this is the case, the engine should be checked in the order and using the procedures below:

1. Check whether the control unit has set any fault codes and rectify this if necessary, in accordance with the “Diagnostic functions” and “Fault codes” chapters.

2. Check and attend to possible symptoms in accordance with the “Fault tracing” chapter.

3. Check and adjust the engine speed regulator as in the “Fine-adjusting the engine speed regulator” in chapter “Parameter settings”.

Diagnostic function

The diagnostic function monitors and checks that the EDC 4 system functions normally.

Diagnostic function

The diagnostic function has the following tasks:

• To detect and locate disturbances.

• To report that disturbances have been detected.

• To guide when troubleshooting.

• Protect the engine and ensure continued operation when serious malfunctions are discovered.

Message regarding malfunction

If the diagnostic function discovers a malfunction in the EDC 4 system, this is notified via the CAN bus or the diagnostic lamp lights up or starts to flash. At the same time, the fault is stored in the control unit memory. As soon as the fault has been attended to and the ignition is turned off and on, the fault code lamp goes out. Both rectified (passive) and un-rectified (active) faults are stored in the control unit and can be read by an authorized workshop.

Fault tracing guide

If the diagnostic button is depressed (for 1-3 seconds) and then released, a fault code is flashed out from the diagnostic lamp. The fault code is found in the fault code list, with information about the reason, reaction and measures to be taken. See chapter on “Fault codes”.

Effect on the engine

The diagnostic function affects the Volvo engine in the following ways:

1. The diagnosis function has detected a minor malfunction that will not damage the engine:

Reaction: The engine is not affected. The diagnostic lamp lights up.

2. The diagnosis function has detected a serious malfunction that makes it impossible to control the engine:

Reaction: The diagnostic lamp starts to flash. Engine is shut off.

Operation

During starting

When the ignition is turned on, the diagnostics lamp and oil pressure and coolant warning lamp light for two seconds. This is to check the lamp function. If the diagnostic lamp flashes after the two seconds, this indicates a serious fault and the engine can not be started. One or more fault codes can then be flashed out. If the diagnostic lamp is lit, there are one or more less serious faults. One or more fault codes can then be flashed out.

During operation

If the diagnostic lamp starts to flash during operation:

1. Reduce engine speed to idling.

2. Press the diagnostic button (for 1-3 seconds).

3. Release the diagnostic button and make a note of the diagnostic trouble code (DTC) that is flashed out. Please refer to “Reading fault codes” below.

4. Look up the fault code in the fault code list and take the necessary measures. See chapter on “Fault codes”