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.

PCM WIRING OR CONNECTORS
1. Turn the ignition off.
2. Using the wiring diagram/schematic as a guide, inspect the wiring and each connector at the PCM.
3. Look for any chafed, pierced, pinched or partially broken wires.
4. Look for broken, bent, pushed out or corroded terminals.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 2
CHECK THE PCM GROUND CIRCUITS
1. Turn the ignition off.
2. Using a 12 volt test light connected to 12 volts, probe the PCM ground circuits.
3. Wiggle test the wiring during the test to check for an intermittent open in the circuit.
  NOTE:
  The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
  
  Is the test light illuminated and bright?
  
  Yes
  - Go To 3
  No
  - Repair the PCM ground circuit(s) for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
CHECK THE PCM FUSED B+ CIRCUIT
1. Using a 12 volt test light connected to ground, probe the PCM Fused B+ circuit.
2. Wiggle test the wiring during the test to check for an intermittent open in the circuit.
  NOTE:
  The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
  
  Is the test light illuminated and bright?
  
  Yes
  - Go To 4
  No
  - Repair the PCM Fused B+ circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
CHECK THE FUSED IGNITION SWITCH CIRCUITS
1. Turn the ignition on.
2. Using a 12 volt test light connected to ground, probe the Fused Ignition Switch circuit.
3. Check the circuit with the ignition off, ignition on/engine not running position and during cranking.
4. Wiggle test the wiring during the test to check for an intermittent open in the circuit.
  NOTE:
  The test light should be illuminated and bright with the ignition on and during cranking. The test light should not be illuminated with the ignition off. Compare the brightness to that of a direct connection to the battery.
  
  Is the test light illuminated as described above?
  
  Yes
  - Test complete.
  No
  - Repair the PCM Fused Ignition Switch circuit for as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .