Additional Testing Using HHT

Compression Testing

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Compression can be tested as an input using the HHT.
A mechanical problem may be present if the difference in engine speed is > 8 rpm for engines 104/112/113, and > 5 rpm for engine 111.
Any engine speed difference will not present itself in the same manner in all engines, so no conclusions can be drawn concerning the affected cylinder.

If the engine speed difference is greater than the set value, perform a compression/cylinder leakage test to determine the affected cylinder.


Cylinder Balance Test

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The cylinder balance test must be performed at idle. If the misfire recognition shutoff threshold is exceeded, a fault will be stored and at the same time the fault count will increases. After repairs, clear the diagnostic memory.


Ignition Circuit Shutoff Test

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Ignition circuit shutoff can only be performed on engine 113.