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Home >> Alfa Romeo >> 2017 >> 4C Base >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Communication Devices >> (Body Control Module (BCM) - Electrical Diagnostics) >> DTC Troubleshooting >> U1701-86 Pcm-ECM (Engine Control Module Node)-Signal Invalid >> Diagnostic Test
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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 CONNECTIONS 
    1. Check that the CAN connections between the Powertrain Control Module (PCM) and the Body Control Module (BCM) are not faulty. In particular, that there are no open circuit or short circuit problems.

      Were there any problems found in the CAN connections between the PCM and BCM?

      Yes 

      • Repair the CAN connections.

      No 

      • Go To  3
  3. CHECK THE POWERTRAIN CONTROL MODULE (PCM) CONNECTORS 
    1. Disconnect/reconnect the PCM connectors and check for a loose pin.

      Were any loose PCM connector pins found?

      Yes 

      • Repair the loose PCM connector pins.

      No 

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

      Were any loose BCM connector pins found?

      Yes 

      • Repair the loose BCM connector pins.

      No 

      • Go To  5
  5. CHECK THE POWERTRAIN CONTROL MODULE (PCM) POWER SUPPLY 
    1. Check that the power supply for the PCM is correct.

      Is the power supply to the PCM correct?

      Yes 

      • Go To  6

      No 

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

      Is the power supply to the BCM correct?

      Yes 

      • Go To  7

      No 

      • Restore the correct power supply to the BCM.
  7. CHECK THE POWERTRAIN CONTROL MODULE (PCM) OPERATION 
    1. Check that the PCM is working properly.

      Does the PCM work properly?

      Yes 

      • Go To  8

      No 

  8. CHECK THE BODY CONTROL MODULE (BCM) OPERATION 
    1. Check that the BCM is working properly.

      Does the BCM work properly?

      Yes 

      • End of diagnosis.

      No