2010 Mercedes Benz SLK 55 AMG (171.473) V8-5.5L (113.989) Copyright ? 2013, ALLDATA 10.52SS Page 1
A L L Diagnostic Trouble Codes ( DTC ): Manufacturer Code Charts
D138
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
2010 Mercedes Benz SLK 55 AMG (171.473) V8-5.5L (113.989) Copyright ? 2013, ALLDATA 10.52SS Page 2
- Is there an open circuit in the CAN bus lines?
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
2010 Mercedes Benz SLK 55 AMG (171.473) V8-5.5L (113.989) Copyright ? 2013, ALLDATA 10.52SS Page 3
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
2010 Mercedes Benz SLK 55 AMG (171.473) V8-5.5L (113.989) Copyright ? 2013, ALLDATA 10.52SS Page 4
