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.
3. Monitor the scan tool and wiggle test the wiring and connectors.
  Is the DTC active or pending?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK FOR AN INTERMITTENT OPEN/HIGH RESISTANCE IN THE (K21) IAT SIGNAL CIRCUIT
1. Turn the ignition off.
2. Verify that the harness connector is properly connected to the MAP Sensor.
3. Disconnect the MAP Sensor harness connector.
4. Disconnect the PCM C2 Sensor harness connector.
5. Measure the resistance of the (K21) IAT Sensor circuit between the MAP harness connector and the PCM C2 Sensor harness connector.
6. Monitor the resistance and wiggle test the wiring and connectors.
  Does the resistance go above 3.0 Ohms while wiggle testing the circuit?
  
  Yes
  - Repair the (K21) IAT Sensor Signal circuit for an intermittent open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CHECK FOR AN INTERMITTENT OPEN/HIGH RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
1. Using a voltmeter, perform a voltage drop test by back probing the (K900) Sensor Ground circuit at the MAP Sensor and PCM C2 harness connectors. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter.
2. Measure the resistance of the (K900) Sensor Ground circuit between the MAP harness connector and the PCM C2 Sensor harness connector.
3. Monitor the resistance and wiggle test the wiring and connectors.
  Does the resistance go above 3.0 Ohms while wiggle testing the circuit?
  
  Yes
  - Go To 4
  No
  - Repair the (K900) Sensor Ground circuit for an intermittent open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK FOR AN INTERMITTENT SHORT TO GROUND IN THE (K21) IAT SIGNAL CIRCUIT
1. Check for continuity between ground and the (K21) IAT Sensor circuit at the MAP harness connector.
2. Monitor the resistance and wiggle test the wiring and connectors.
  Is there continuity between ground and the (K21) IAT Sensor circuit while wiggle testing the circuit?
  
  Yes
  - Repair the (K21) IAT Sensor Signal circuit for an intermittent short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
MAP SENSOR
1. Reconnect the PCM C2 harness connector.
2. Turn the ignition on.
3. With the scan tool, read the IAT Sensor voltage.
  NOTE:
  The sensor voltage should be approximately 5.0 volts (plus or minus.1 volt) with the connector disconnected.
4. Turn the ignition off.
5. Connect a jumper between the (K900) Sensor Ground circuit and the (K21) IAT Sensor Signal circuit in the MAP Sensor harness connector.
6. Turn the ignition on.
7. With the scan tool, read the IAT Sensor voltage.
  NOTE:
  The sensor voltage should be approximately 0.0 volts (plus or minus.1 volt) with the jumper in place.
  
  Does the scan tool display the voltage as described above?
  
  Yes
  - Replace the MAP Sensor in accordance with the Service Information. Refer to SENSOR, MANIFOLD AIR PRESSURE (MAP), REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 6
CHECK RELATED PCM AND COMPONENT CONNECTIONS
1. Perform any Service Bulletins that apply.
2. Disconnect all PCM harness connectors.
3. Disconnect all related in-line harness connections (if equipped).
4. Disconnect the related component harness connectors.
5. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Check for spread terminals and verify proper terminal tension.
  Repair any conditions that are found.
6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
9. With the scan tool, erase DTCs.
10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
11. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Replace the Powertrain Control Module in accordance with the Service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  - Test complete.