The compression test is a comparative test and shows whether any cylinder deviates from the others.
We recommend that you read through the entire text before you begin the test.
Note:
The test is run in two or five steps depending on the number of cylinders, and lasts between one and two minutes.
The result is displayed as the difference in rpm per cylinder, compared with the average rpm.
A positive value indicates that the compression is poorer than average and a negative value indicates that it is better.
In order to start the test you must perform the following:
Test conditions:
Erase any fault codes.
Run the engine until the coolant temperature exceeds 40°.
Parking brake applied.
The compressed air system must be full so that the compressor does not charge.
The clutch and brake pedals must be released.
The retarder, white smoke limiter and exhaust brake must be turned off.
The battery must be fully charged when the test is performed so that the starter motor can turn the engine quickly enough.
Procedure:
Engine idling.
Start the function and follow the instructions in the program.
A dialogue box shows the test conditions; check these and press "OK".
The function is complete.