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.

ACTIVE DTC
NOTE:
Check for contaminates that may have damaged an O2 Sensor: contaminated fuel, unapproved silicone, oil and coolant.
1. Start the engine.
2. Allow the engine to reach normal operating temperature.
3. With the scan tool, read DTCs.
  NOTE:
  It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.
  
  Is the DTC Active or Pending at this time?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
EXHAUST LEAK
NOTE:
A thorough exhaust leak test must be completed before removing an O2 Sensor or any other part from the exhaust system. Do not remove any parts before an exhaust leak check has been completed.

NOTE:
An exhaust leak may cause the downstream fuel adaptive to rail out, resulting in a false O2 Sensor failure.
1. Perform the diagnostic procedure for CHECKING THE EXHAUST SYSTEM FOR LEAKS. Refer to CHECKING THE EXHAUST SYSTEM FOR LEAKS .
  Were any problems found?
  
  Yes
  - Repair as necessary in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CHECKING THE OXYGEN SENSOR OPERATION
1. Perform the CHECKING THE OXYGEN SENSOR OPERATION diagnostic procedure. Refer to DIAGNOSIS AND TESTING .
  Were any problems found?
  
  Yes
  - Repair as necessary in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 4
CHECK THE FUEL DELIVERY SYSTEM
1. Perform the CHECKING THE FUEL DELIVERY SYSTEM test procedure. Refer to CHECKING THE FUEL DELIVERY SYSTEM (HARD START) .
  Were any problems found with the fuel system?
  
  Yes
  - Perform the appropriate repair.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
O2 SENSOR
1. Turn the ignition off.
2. Replace the O2 Sensor accordance with the service information and reconnect the harness connector. Refer to SENSOR, OXYGEN, REMOVAL .
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Start the engine and allow it to idle long enough for the O2 Sensor to enter closed loop operation.
6. With the scan tool, view DTCs.
  Did the DTC return?
  
  Yes
  - Go To 6
  No
  - Repair is complete.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
POWERTRAIN CONTROL MODULE (PCM)
NOTE:
Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the O2 Sensor 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. Verify that there is good pin to terminal contact in the O2 Sensor and Powertrain Control Module harness connectors.
4. Perform any Technical Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace and program the Powertrain Control Module in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL and PROGRAM THE PCM (POWERTRAIN CONTROL MODULE) .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .