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
NOTE:
If there are any 5-Volt Reference DTCs present, repair those DTCs before proceeding with this test.
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
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT
1. Turn the ignition off.
2. Disconnect the Boost Pressure Sensor harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (F856) 5-Volt Supply circuit at the Boost Pressure Sensor harness connector.
  Does the voltage read 5.0 volts?
  
  Yes
  - Go To 3
  No
  - Repair the (F856) 5-Volt Supply circuit for an open or short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST.
CHECK THE (K37) BOOST PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Check for continuity between ground and the (K37) Boost Pressure Sensor Signal circuit at the Boost Pressure Sensor harness connector.
  Is there continuity between ground and the (K37) Boost Pressure Sensor Signal circuit?
  
  Yes
  - Repair the (K37) Boost Pressure Sensor Signal circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST.
  No
  - Go To 4
CHECK THE (K37) BOOST PRESSURE SENSOR SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K37) Boost Pressure Sensor Signal circuit between the Boost Pressure Sensor harness connector and the PCM C2 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (K37) Boost Pressure Sensor Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST.
CHECK THE BOOST PRESSURE SENSOR
1. Reconnect the Boost Pressure Sensor harness connector.
2. Reconnect the PCM C2 harness connector.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Turn the ignition off.
6. Disconnect the Boost Pressure Sensor harness connector.
7. Connect a jumper between the (K37) Boost Pressure Sensor Signal circuit and the (F856) 5-Volt Supply circuit.
  NOTE:
  Be careful not to spread the terminals.
8. Turn the ignition on.
9. With the scan tool, view PCM DTCs.
  NOTE:
  The scan tool should display the P0238-TURBO BOOST PRESSURE SENSOR CIRCUIT HIGH DTC with the jumper connected.
  
  Does the scan tool display the DTC as described above?
  
  Yes
  - Replace the Boost Pressure Sensor in accordance with the Service Information.
  - Perform the 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, 16V Turbo .
  No
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  - Test complete.