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Home >> Alfa Romeo >> 2017 >> 4C Base >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> (Instrument Cluster - Electrical Diagnostics) >> DTC Troubleshooting >> U1700-86-Body Computer Module (BCM) - Signal Invalid >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    1. With the scan tool, read DTCs.

      Is the DTC active?

      Yes 

      • Go To  2

      No 

      • Test complete.
  2. CHECK THE CAN LINE WIRING BETWEEN THE INSTRUMENT PANEL CLUSTER AND THE BODY CONTROL MODULE 
    1. Check that the CAN connections between the Instrument Panel Cluster (IPC) and the Body Control Module (BCM) are not faulty. In particular, that there are no open circuit or short circuit problems.

      Were there any faulty conditions?

      Yes 

      • Restore or, if necessary, replace the wiring.

      No 

      • Go To  3
  3. CHECK THE INSTRUMENT PANEL CLUSTER CONNECTORS 
    1. Disconnect / reconnect the IPC connectors and check for loose pins

      Were there any loose pins found?

      Yes 

      • Restore the connector to a correct working order.

      No 

      • Go To  4
  4. CHECK THE BODY CONTROL MODULE CONNECTORS 
    1. Disconnect / reconnect the BCM connectors and check for loose pins

      Were there any loose pins found?

      Yes 

      • Restore the connector to a correct working order.

      No 

      • Go To  5
  5. CHECK THE INSTRUMENT PANEL CLUSTER POWER SUPPLY 
    1. Check that the power supply to the IPC is correct.

      Is the power supply to the IPC correct?

      Yes 

      • Go To  6

      No 

      • Restore the correct power supply.
  6. CHECK THE BODY CONTROL MODULE POWER SUPPLY 
    1. Check that the power supply to the BCM is correct.

      Is the power supply to the BCM correct?

      Yes 

      • Go To  7

      No 

      • Restore the correct power supply.
  7. CHECK THE INSTRUMENT PANEL CLUSTER 
    1. Check that the IPC is operating correctly.

      Is the IPC operating correctly?

      Yes 

      • Go To  8

      No 

      • Replace the Instrument Panel Cluster (IPC) in accordance with the Service Information. Refer to REMOVAL AND INSTALLATION .
  8. CHECK THE BODY CONTROL MODULE 
    1. Check that the BCM is operating correctly.

      Is the BCM operating correctly?

      Yes 

      • Test complete.

      No