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 and record on the repair order.
  Is the DTC active or pending?
  
  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 (N4) FUEL LEVEL SIGNAL 1 CIRCUIT FOR A SHORT TO VOLTAGE
1. Disconnect the Fuel Pump Module C1 harness connector.
2. Measure the voltage on the (N4) Fuel Level Sensor Signal circuit at the Fuel Pump Module C1 harness connector.
  Is the voltage above 5.1 volts?
  
  Yes
  - Repair the (N4) Fuel Level Sensor Signal circuit for a short to voltage.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .
  No
  - Go To 3
CHECK THE (N4) FUEL LEVEL SENSOR SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the BCM C6 harness connector.
3. Measure the resistance of the (N4) Fuel Level Sensor Signal circuit between the Fuel Pump Module C1 harness connector and the BCM C6 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Replace the Fuel Level Sending Unit 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 4
CHECK THE (G109) FUEL LEVEL SENSE RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (G109) Fuel Level Sense Return circuit between the Body Control Module C6 harness connector and the Fuel Pump Module C1 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (G109) Fuel Level Sense Return circuit for an open or high resistance.
  - Perform the BODY VERIFICATION TEST. Refer to BODY CONTROL MODULE (BCM) - BODY VERIFICATION TEST - 500 - EXCEPT ELECTRIC .
FUEL LEVEL SENSOR
1. Reconnect the BCM C6 harness connector.
2. Connect a jumper between the (N4) Fuel Level Sensor Signal circuit and the (G109) Fuel Level Sense Return circuit at the Fuel Pump Module C1 harness connector.
3. Turn the ignition on.
4. With the scan tool, read DTCs and record on the repair order.
  NOTE:
  The P0462-FUEL LEVEL SENSOR 1 CIRCUIT LOW DTC should display as active or pending with the jumper in place.
  
  Does the scan tool display as described above?
  
  Yes
  - Replace the Fuel Level Sensor 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 6
BODY CONTROL MODULE (BCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Fuel Pump Module and the BCM.
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Fuel Pump Module and the BCM harness connectors.
4. 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 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 .