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 ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
1. Turn the ignition on.
2. 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 (L58) LEFT DAYTIME RUNNING LAMP DRIVER CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the Left Front Lamp Assembly C2 harness connector.
3. Disconnect the BCM C1 harness connector.
4. Measure the resistance between ground and the (L58) Left Daytime Running Lamp Driver circuit.
  Is the resistance above 10K Ohms?
  
  Yes
  - Go To 3
  No
  - Repair the short to ground in the (L58) Left Daytime Running Lamp Driver circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .
CHECK THE BCM FOR CORRECT OPERATION
1. Reconnect the BCM C1 harness connector.
2. Connect a 12-volt test light between ground and the (L58) Left Daytime Running Lamp Driver circuit at the Left Front Lamp Assembly C2 harness connector.
3. Turn the ignition on.
4. Actuate the DRL
  Does the test light illuminate brightly?
  
  Yes
  - Replace the Left DRL Bulb in accordance with the Service Information. Refer to UNIT, FRONT LAMP, LOWER, REMOVAL and UNIT, FRONT LAMP, UPPER, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .
  No
  - Replace the Body Control Module (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 .