Troubleshooting
Troubleshooting BCM-U030046
Checking diagnostic trouble codes in the central electronic module (CEM)
Checking diagnostic trouble codes (DTCs) in the central electronic module
Checking other diagnostic trouble codes (DTCs)
In the event of communication problems, the fault may exist in other parts of the communications network.
The role of the central electronic module is to generally control the communications network and to store diagnostic trouble codes (DTCs) in the event of communication problems between control modules.
If there are diagnostic trouble codes (DTCs) stored for communication problems in the central electronic module, stop the fault tracing and fault trace the central electronic module.
Were diagnostic trouble codes (DTCs) for communication problems stored in the central electronic module?
Yes - DONE
No - No Fault Found
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DONE - DONE
No Fault Found - Checking the diagnostic trouble codes (DTCs)
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Checking the diagnostic trouble codes (DTCs)
- Ignition on
- Wait approximately 60 seconds.
- Read the status of the diagnostic trouble code.
Is the status of the diagnostic trouble code permanent?
Yes - Checking cables and connections
- Intermittent malfunction
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Checking cables and connections
- Ignition off
Check the brake control module (BCM) connector for damaged or bent pins as well as contact resistance and oxidation.
Check the cables for CAN-communication between the bra control module (BCM) and central electronic module (CEM) for open circuit, short-circuit to ground and short-circuit to voltage.
Also check that the cables are not positioned too close to a source of interference, such as a cellular phone.
Remedy as necessary.
Other information
- Checking wiring and terminals Checking Wiring And Terminals
Continue - Verification
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Troubleshooting information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - Exit fault-tracing
No - Attempt New Test
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Attempt New Test - Checking diagnostic trouble codes in the central electronic module (CEM)
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Verification
Verification
Hint: After carrying out the repair, check that the malfunction has been remedied.
- Ignition off
- Reconnect the connectors, components, etc.
- Test-drive the vehicle according to Test Drive Form (DSTC (dynamic stability and traction control) /brake control module), description Test Drive Form (DSTC (Dynamic Stability And Traction Control) /Brake Control Module), Description.
Note! Do not turn off the ignition between test-driving and reading out diagnostic trouble codes. This is to obtain the correct status of the diagnostic trouble codes.
Then read out the diagnostic trouble code's status without turning off the ignition after the test-drive.
Is the status of the diagnostic trouble code intermittent?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFICATION FAILED - Troubleshooting information
VERIFIED - FAULT FOUND
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Intermittent malfunction
Hint: The diagnostic trouble code status indicates that the brake control module (BCM) has previously registered a malfunction, but the malfunction is no longer active.
Check the connectors of the brake control module (BCM) and the central electronic module (CEM) for contact resistance and oxidation.
Also check that the CAN-communication cables are not positioned too close to a source of interference, such as a cellular phone.
Remedy as necessary.
Continue - DONE
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Troubleshooting information
Information
Fault-tracing information
If the fault is intermittent, do not verify fault-tracing if the fault does not recur.
It is possible to view the information again, or leave fault-tracing for this diagnostic trouble code (DTC).
Do you want to view the information again?
Yes - Attempt New Test
No - FAULT FOUND
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Attempt New Test - Checking diagnostic trouble codes in the central electronic module (CEM)
FAULT-TRACING FAILED - FAULT FOUND
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