What Is Volvo Engine Diagnostic Function
Diagnostic function
The diagnostic function monitors and checks that the Volvo Penta Engine 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”
If the diagnostic lamp starts to flash, the engine will be emergency stopped.
IMPORTANT! On VE engines, there is a function in the system which makes it possible to start the engine again and run it for about 25 seconds. This is so that the vehicle can be moved from a railway level crossing etc.
Reading fault codes
Fault codes can either be read via:
- The VODIA tool (including the Penta EDC4 software). Please refer to the “VODIA User’s Guide” for advice on use
- Diagnostic lamp
- CAN
Diagnostic lamp
If the diagnostic lamp is illuminated or flashes, a fault code can be read by pressing the diagnostic button (for 1-3 seconds) and then releasing it. The diagnostic lamp goes out, and a fault code is then flashed out.
The fault code consists of three groups of flashes, separated by a pause of two seconds.
The first and third group consist of short flashes (0.4 s).
The second group consists of long flashes (0.8 s). A fault code is obtained by counting the number of flashes in each group.
Example: (2 short) pause (2 long) pause
(1 short) = Fault code 2.2.1
The fault code is stored and can be read as long as the fault remains. You can find information about cause, reaction and actions in the fault code list.
Please refer to “Fault codes”.
Read as follows:
1. Press the diagnostic button (for 1-3 seconds).
2. Release the diagnostic button and make a note of the fault that is flashed out.
3. Repeat items 1-2. A new fault code is flashed out if more are stored. Repeat until the first fault code is repeated.
NOTE! When the first fault code returns, all fault codes have been read.
When all faults have been rectified:
1. Turn the ignition on and off.
2. Press the diagnostic button (for 1-3 seconds) to check whether any faults remain.
3. If there are no active faults, the diagnostic lamp will give two short flashes, in other cases the remaining non-rectified faults will be flashed out again.
CAN frames - EDC 4
The CAN - BUS has the following adjustment:
The node address of EDC4 is 0.
The rate of transmission is 250 kBaud.
After switching power on EDC4 waits 10 sec for the other nodes before the time out diagnostic starts.
During the 10 second after switching power on a receive message must be received 4 times at least, other wise there will be a time out error.
When the power supply drops below 9Volt, EDC4 will admit the other nodes a time out of 30sec.
A receive message can be missing 8 times in a row before a time out Error will be generated.
1. If a message of Torque Speed Control has generated the time out, the Limp Home Function will be started. If the message will be received again it will not be accepted anymore by the EDC4 until the EDC4 is restarted again.
2. In case of other receive messages that generated a time out the last received value will be used. If a message is received again it will be accepted automatically.
The node address for the received messages are 3. Only the request and genset engine stop request messages can be received from any node on the BUS.
The priority, resolution, repetition rate and all other information is outlined in the CAN Specification for EDC4.