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.

CHECK FOR AN INTERMITTENT CONDITION
1. Turn the ignition on.
2. With the scan tool, clear all DTCs.
3. Activate the Stop Lamps.
4. With the scan tool, read DTCs.
  Does the scan tool display this DTC as 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 CENTER HIGH MOUNTED STOP LAMP (CHMSL) BULBS
NOTE:
This DTC will set if three or four bulbs are bunt out.
1. Inspect the harness connector at the CHMSL for correct connection.
2. Inspect the CHMSL for burnt out or damaged bulbs.
  Are any concerns present?
  
  Yes
  - Replace the CHMSL Bulbs or Lamp Assembly as needed in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .
  No
  - Go To 3
CHECK THE BCM FOR CORRECT OPERATION
1. Disconnect the CHMSL harness connector.
2. Connect a 12-volt test light between the (L56) Brake Lamp Switch Output circuit and the (Z941) ground circuit at the CHMSL harness connector.
3. Turn the ignition on.
4. Activate the Stop Lamps.
  Does the test light illuminate with the Stop Lamps activated?
  
  Yes
  - If the test light was dim, use the wiring diagrams as a guide and check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
  - If the test light was bright, test complete. The condition or conditions that originally set this DTC are not present at this time.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .
  No
  - Replace the BCM in accordance with the Service Information. Refer to MODULE, BODY CONTROL, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .