Diagnostic Test

WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.

VERIFY DTC IS ACTIVE
NOTE:
Make sure the battery voltage is between 10 and 16 volts before proceeding.
1. With the scan tool, erase DTCs.
2. Turn the ignition off.
3. Turn the ignition on and wait five seconds.
4. With the scan tool, read active DTCs.
  Does the scan tool display this DTC active?
  
  Yes
  - Go To 2
  No
  - Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .
CHECK THE FUSED B(+) CIRCUIT FOR AN OPEN OR SHORT
1. Turn the ignition off.
2. Disconnect the VTM harness connector.
3. Using a 12-volt test light connected to ground, check the Fused B(+) circuit.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 3
  No
  - Repair the open or short in the Fused B(+) circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .
CHECK THE GROUND CIRCUIT FOR AN OPEN
1. Using a 12-volt test light connected to 12-volts, check the Ground circuit.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 4
  No
  - Repair the open in the Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .
CHECK THE CAN B BUS CIRCUIT FOR AN OPEN
1. Measure the resistance of the CAN B Bus (-) circuit between the VTM harness connector and the BCM harness connector.
2. Measure the resistance of the CAN B Bus (+) circuit between the VTM harness connector and the BCM harness connector.
  Are the resistances below 5.0 Ohms?
  
  Yes
  - Replace the VTM in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .
  No
  - Repair the open in the CAN B Bus circuit. Inspect the connector for damage.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .