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
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 - ELECTRIC .
CHECK THE (F915) FUSED IGNITION CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the Humidity Sensor harness connector.
3. Turn the ignition on.
4. Using a 12-volt test light connected to ground, check the (F915) Fused Ignition circuit at the Humidity Sensor harness connector.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 3
  No
  - Repair the open or short to ground in the (F915) Fused Ignition circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - ELECTRIC .
CHECK THE (Z942) GROUND CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Using a 12-volt test light connected to 12-volts, check the (Z942) Ground circuit at the Humidity Sensor harness connector.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 4
  No
  - Repair the open in the (Z942) Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - ELECTRIC .
CHECK THE (D501) LIN BUS CIRCUIT FOR AN OPEN
1. Turn the ignition on.
2. Measure the voltage between ground and the (D501) LIN Bus circuit at the Humidity Sensor harness connector.
  Is the voltage above 5.0 volts?
  
  Yes
  - Replace the Humidity Sensor in accordance with the Service Information. Refer to SENSOR, HUMIDITY, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - ELECTRIC .
  No
  - Repair the open in the (D501) LIN Bus circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - ELECTRIC .