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.

ECT SENSOR OPERATION
NOTE:
For this test to be valid, the thermostat must be operating correctly.

NOTE:
This test works best if performed on a cold engine (cold soak).
1. Ignition on, engine not running.
2. With the scan tool, read the Engine Coolant Temperature (ECT) Sensor value. If the engine was allowed to sit overnight (cold soak), the temperature value should be a sensible value that is somewhere close to the ambient temperature.
  NOTE:
  If engine coolant temperature is above 82°C (180°F), allow the engine to cool until 65°C (150°F) is reached.
3. Start the Engine.
4. During engine warm-up, monitor the ECT Sensor value. The temperature value change should be a smooth transition from start up to normal operating temperature 82°C (180°F). The value should reach at least 82°C (180°F).
  Did the ECT value increase smoothly and did it reach at least 82°C (180°F)?
  
  Yes
  - Go To 2
  No
  - Verify that there is good pin to terminal contact in the ECT Sensor and Powertrain Control Module connectors. If OK, replace the Engine Coolant Temperature Sensor. Refer to SENSOR, COOLANT TEMPERATURE, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
ACTIVE DTC
1. Diagnose all other DTCs before continuing.
2. Start the engine.
3. Allow the engine to reach normal operating temperature.
4. 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 3
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
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 FUEL PRESSURE
1. Perform the CHECKING THE FUEL DELIVERY SYSTEM test procedure. Refer to CHECKING THE FUEL DELIVERY SYSTEM (HARD START) .
  Were any fuel system issues found?
  
  Yes
  - Perform the appropriate repairs.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
MAP SENSOR OPERATION
1. Perform the CHECKING THE MAP SENSOR OPERATION test procedure. Refer to CHECKING THE MAP SENSOR OPERATION .
  Were any problems found with the MAP Sensor?
  
  Yes
  - Perform the appropriate repair.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 6
ENGINE MECHANICAL PROBLEM
1. Turn the ignition off.
2. Check for any of the following conditions/mechanical problems:
  - AIR INDUCTION SYSTEM - must be free from leaks.
  - ENGINE VACUUM - must be at least 13 inches in neutral
  - ENGINE VALVE TIMING - must be within specifications
  - ENGINE COMPRESSION - must be within specifications
  - ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
  - ENGINE PCV SYSTEM - must flow freely
  - TORQUE CONVERTER STALL SPEED - must be within specifications
  - POWER BRAKE BOOSTER - no internal vacuum leaks
  - FUEL - must be free of contamination
  - FUEL INJECTOR - plugged or restricted injector; control wire not connected to correct injector
  Are there any engine mechanical problems?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 7
O2 SENSOR
1. Turn the ignition off.
2. Replace the O2 Sensor and reconnect the harness connector.
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 8
  No
  - Repair is complete.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the related Sensors 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 related Sensor and Powertrain Control Module 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 .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .