Mercedes-Benz Mercedes Benz OEM Parts Mercedes Benz OE Replacement Parts
D138
Mercedes Benz Truck G 550 (463.236) V8-5.5L (273.963) Diagnostic Trouble Codes Page 26
The message from the auxiliary oil pump is not available on the CAN bus.
Possible cause:
- M42 (Electric transmission oil pump) / N89 (Transmission oil additional pump control unit)
Affected functions:
- Engine start
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Test 1: Check component M42 (Electric transmission oil pump).
1. Check component M42 (Electric transmission oil pump).
Operation number of operation texts and work units or standard texts and flat rates:27-0641Test prerequisite
- Battery voltage is OK.
Test sequence
- Switch off ignition.
- Disconnect connector at component N89 (Transmission oil additional pump control unit).
- Use multimeter to check voltage directly at jacks of wiring harness for component N89 (Transmission oil additional pump control unit).
- Switch on ignition.
Measure direct voltage with multimeter between 1 and 4Specified value
- Voltage [8,5...16,4] V
Question
- Is the measurement value OK?
YES
The measurement value is OK.Further test:Test CAN wiring for Open circuit.Test sequence
- Switch off ignition.
- Disconnect connector at component N89 (Transmission oil additional pump control unit).
- Expose component X30/21 (Drive train CAN voltage distributor connector).
CAN bus HighMeasure resistance with multimeter between (X30/21) 2 and (N89) 3CAN bus LowMeasure resistance with multimeter between
(X30/21) 1 and (N89) 2Question
- Is there an open circuit in the CAN bus lines?
Mercedes Benz Truck G 550 (463.236) V8-5.5L (273.963) Diagnostic Trouble Codes Page 27
YES
There is an open circuit in the CAN bus lines.Cause
- CAN signal interruption
- Component X30/21 (Drive train CAN voltage distributor connector) is defective.
REMEDY
- Check line from control module N89 (Transmission oil additional pump control unit) to component X30/21 (Drive train CAN voltage
distributor connector).
- Replace component X30/21 (Drive train CAN voltage distributor connector).
End of test
Mercedes Benz Truck G 550 (463.236) V8-5.5L (273.963) Diagnostic Trouble Codes Page 28
NO
There is no open circuit in the CAN bus lines.Cause
- There is an internal fault in component N89 (Transmission oil additional pump control unit).
- There is an internal fault in component M42 (Electric transmission oil pump).
REMEDY
- Replace component M42 (Electric transmission oil pump).
NOTE
- No further actions are required.
End of test
NO
The measurement value is not OK.Possible cause and remedy
- Check fuse F1/6f76 (Fuse 76) in component N10/1 (Front SAM control unit with fuse and relay module) for tight installation and corrosion.
- Check lines and plug connection on components M42 (Electric transmission oil pump) and N10/1 (Front SAM control unit with fuse and relay
module) for loose contacts, damages, interruptions, etc. and if necessary, repair or replace parts.
End of test
