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 DTC
NOTE:
Diagnose any CAN - C Communication DTCs before continuing.
1. Turn the ignition on.
2. With the scan tool, read DTCs.
  Is the DTC active?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT DTC diagnostic procedure. Refer to INTERMITTENT CONDITION .
AMBIENT AIR TEMPERATURE SENSOR
1. Turn the ignition off.
2. Disconnect the AAT harness connector.
3. Turn the ignition on.
4. With the scan tool, read DTCs.
  NOTE:
  The P0073-AMBIENT AIR TEMPERATURE SENSOR HIGH DTC should be active or pending with the AAT harness connector unplugged.
  
  Does the scan tool display as described above?
  
  Yes
  - Replace the Ambient Air Temperature Sensor in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 3
CHECK THE (G31) AAT SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the BCM harness connector.
3. Check for continuity between ground and the (G31) AAT Signal circuit at the Ambient Air Temperature Sensor harness connector.
  Is there continuity between ground and the (G31) AAT Signal circuit?
  
  Yes
  - Repair the (G31) AAT Signal circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 4
CHECK FOR THE (G31) AAT SIGNAL CIRCUIT SHORTED TO THE (G931) AAT SENSOR GROUND CIRCUIT
1. Check for continuity between the (G31) AAT Signal circuit and the (G931) AAT Sensor Ground circuit at the Ambient Air Temperature Sensor harness connector.
  Is there continuity between the (G31) AAT Signal circuit and the (G931) AAT Sensor Ground circuit?
  
  Yes
  - Repair the (G31) AAT Signal circuit for a short to the (G931) AAT Sensor Ground circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 5
BODY CONTROL MODULE (BCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Ambient Air Temperature Sensor and the Body Control Module (BCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Perform any Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - 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 .