Operation CHARM: Car repair manuals for everyone.

P2561


Implausible data were received from the air conditioning.


Possible cause:

- Hybrid CAN bus
Affected functions:

- Engine diagnosis
- Engine start
- Engine output

-------------------------------------------------

Test 1: Test CAN connection to X30/44 (Hybrid CAN potential distributor connector).

1. Test CAN connection to X30/44 (Hybrid CAN potential distributor connector).
Check CAN lines of hybrid CAN bus.
Figure legend

- Component X30/44 (Hybrid CAN potential distributor connector) is located behind component N10/1 (Front SAM control unit with fuse and relay module).
Test prerequisite

- CAN communication is faulty.
- Relevant fault codes are present, or communication with control module cannot be established.
Test sequence

- Switch off ignition.
- Disconnect all electrical connectors at component X30/44 (Hybrid CAN potential distributor connector).
- Measure resistance with multimeter between sockets ( X30/44 ) 1 and ( X30/44 ) 2
NOTE

- Perform measurement at all electrical connectors.
Specified value(Valid for four measurements)

- Resistor[ 47.5...52.5] kohms
Specified value(Only valid for one measurement)

- Resistor[ 23.5...27.5] kohms
Question

- All readouts o.k. ?







YES
Total resistance of hybrid CAN bus
REQUIREMENT

- The measurement values are OK.
Additional measures

- Perform measurement at component X30/44 (Hybrid CAN potential distributor connector).
- Measure resistance with multimeter between pins ( X30/44 ) 1 and ( X30/44 ) 2
Adapter cable no. W220 589 00 99 38 may be used.Warning!Repeat measurement at all slots of the component.Specified value

- [55...65]ohms
Question

- Is the measured value within the specified value range?













YES
Test procedure ground cable
Preconditions

- The measurement value is OK.
Further procedure

- Measurement with multimeter
- Disconnect 3-pin plug from component X30/44 (Hybrid CAN potential distributor connector).
- Measure resistance with multimeter between socket (X30/44) 3 and ground (Kl. 31)
Specified value

- [< 5]ohms
Question:

- Is the measured value within the specified value range?







YES
Test procedure ground cable
Preconditions

- The measurement value is OK.
Further procedure

- Connect all electrical connectors at component X30/44 (Hybrid CAN potential distributor connector).
- Perform test 'Power supply' from the complete list of guided tests.
Continue with button "F2"

NO
Test procedure ground cable
Preconditions

- The measurement value is not OK.
Possible cause and remedy

- Connect all electrical connectors at component X30/44 (Hybrid CAN potential distributor connector).
- Check electrical lines and connectors for short circuit, open circuit, loose seating and damage using the appropriate wiring diagram.
End of test

NO
Total resistance of hybrid CAN bus
Preconditions

- The measurement value is not OK.
Possible cause and remedy

- X30/44 (Hybrid CAN potential distributor connector)
- Check electrical lines and connectors for short circuit, open circuit, loose seating and damage using the appropriate wiring diagram.
End of test

NO
Check component X30/44 (Hybrid CAN potential distributor connector).
REQUIREMENT

- At least one of the measured values is not o.k.
Additional measures

- Perform measurement at component X30/44 (Hybrid CAN potential distributor connector).
- Measure resistance with multimeter between pins ( X30/44 ) 1 and ( X30/44 ) 2
Adapter cable no. W220 589 00 99 38 may be used.Warning!Repeat measurement at all slots of the component.Specified value

- [55...65]ohms
Question

- Is the measured value within the specified value range?













YES
Check CAN lines of hybrid CAN bus.
Preconditions

- The measurement value is OK.
Test sequence

- Connect all electrical connectors at component X30/44 (Hybrid CAN potential distributor connector).
- Disconnect electrical connector at the affected control unit.
- Perform a resistance measurement of the CAN lines between the electrical connector of the control unit and component X30/44 (Hybrid CAN potential distributor connector).
Warning

- Perform measurement as per the current wiring diagram.
Specified value

- [55...65]ohms
Question

- Measured value o.k.?







YES
Check CAN lines of hybrid CAN bus.
Preconditions

- The measurement value is OK.
Further procedure

- Perform test 'Power supply' from the complete list of guided tests.
Continue with button "F2"

NO
Check CAN lines of hybrid CAN bus.
Preconditions

- The measurement value is not OK.
Possible cause and remedy

- Check electrical lines and connectors for short circuit, open circuit, loose seating and damage using the appropriate wiring diagram.
End of test

NO
Check component X30/44 (Hybrid CAN potential distributor connector).
Preconditions

- At least one of the measured values is not o.k.
Possible cause and remedy

- X30/44 (Hybrid CAN potential distributor connector)
Continue with button "F2"

Check CAN lines of hybrid CAN bus.
Preconditions

- Component X30/44 (Hybrid CAN potential distributor connector) was exchanged.
Test sequence

- Connect all electrical connectors at component X30/44 (Hybrid CAN potential distributor connector).
- Disconnect electrical connector at the affected control unit.
- Perform a resistance measurement of the CAN lines between the electrical connector of the control unit and component X30/44 (Hybrid CAN potential distributor connector).
Warning

- Perform measurement as per the current wiring diagram.
Specified value

- [55...65]ohms
Question

- Measured value o.k.?







YES
Check CAN lines of hybrid CAN bus.
Preconditions

- The measurement value is OK.
Further procedure

- Perform test 'Power supply' from the complete list of guided tests.
Continue with button "F2"

NO
Check CAN lines of hybrid CAN bus.
Preconditions

- The measurement value is not OK.
Possible cause and remedy

- Check electrical lines and connectors for short circuit, open circuit, loose seating and damage using the appropriate wiring diagram.
End of test