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.

DIAGNOSTIC TROUBLE CODE (DTC) IS ACTIVE
1. Attempt to start the engine. If the engine will not start, crank the engine for five seconds.
  WARNING:
  When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
2. Using the scan tool, read the active DTCs.
  Does the scan tool display P0628-00-FUEL PUMP CONTROL CIRCUIT LOW?
  
  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 INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
FUEL PUMP RELAY
1. Turn the ignition off.
2. Install a known good Fuel Pump Relay.
3. Attempt to start the engine.
  Does P0628-00 return?
  
  Yes
  - Go To 3
  No
  - Replace the Fuel Pump Relay.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
FUEL PUMP CONTROL CIRCUIT SHORTED TO GROUND
1. Turn the ignition off.
2. Remove the Fuel Pump Relay.
3. Disconnect the Powertrain Control Module (PCM) C1 harness connector.
4. Measure the resistance between ground and the (A64) Electric Fuel Pump Relay Feed circuit in the PCM C1 harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the short to ground in the (A64) Electric Fuel Pump Relay Feed circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
EXCESSIVE RESISTANCE IN THE (A64) ELECTRIC FUEL PUMP RELAY FEED CIRCUIT
1. Measure the resistance of the (A64) Electric Fuel Pump Relay Feed circuit between the relay terminal and the Powertrain Control Module (PCM) C1 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the high resistance in the (A64) Electric Fuel Pump Relay Feed circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Relay and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Perform any Technical Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .