Diagnostic Test
WARNING: This page is about a different car, the 2014 Fiat 500c and 2014 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.
- ACTIVE DTC
- Turn the ignition off.
- If possible, allow the vehicle to sit with the ignition off for more than 480 minutes in an environment where the temperature is consistent and above -7° C (19.4° F).
- Test drive the vehicle. The vehicle must exceed 48 km/h (30 mph) during the test drive. Do not cycle the ignition off when the test drive is completed.
- With the scan tool, select View the DTCs.NOTE:
All ECT, Intake Air and Ambient Air Temperature Sensor codes must be diagnosed and repaired before continuing.
NOTE:In cold weather, this DTC could be set by a high powered block heater and no repair would be required.
Is the DTC Active or Pending at this time?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
- TEMPERATURE SENSOR CIRCUIT
- With the scan tool, read the ECT, Ambient Air Temp and Intake Air Temp Sensor temp values.
- Start the engine.
- Allow the engine to reach normal operating temperature while monitoring the three Sensor temperature values.
Is the temperature for each of the Sensors increasing properly?
Yes
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
No
- Go To 3
- TEMPERATURE SENSOR
- Disconnect the suspected sensor.
- Ignition on, engine not running.
- With the scan tool, read the voltage of the suspected sensor.
- Connect a jumper wire between the Sensor Signal circuit and the Sensor ground circuit.
Did the voltage reading start at 4.8 to 5.0 Volts and decrease to 0 Volts when the jumper wire was installed?
Yes
- Verify that there is good pin to terminal contact in the Sensor and Control Module connectors. If OK, replace the appropriate Temperature Sensor.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 4NOTE:
Remove the jumper wire before continuing.
- CHECK THE TEMPERATURE SENSOR SIGNAL CIRCUIT FOR EXCESSIVE RESISTANCE
- Turn the ignition off.
- Disconnect the PCM harness connector.
- Measure the resistance of the Sensor Signal circuit from the Sensor harness connector to the PCM harness connector for the ECT Sensor and IAT Sensor.
- Measure the resistance of the AAT Sensor Signal circuit from the Sensor harness connector to the BCM harness connector.
Is the resistance above 5.0 Ohms?
Yes
- Repair the excessive resistance in the Temperature Sensor Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 5
- CHECK THE SENSOR GROUND CIRCUIT FOR EXCESSIVE RESISTANCE
- Measure the resistance of the Sensor ground circuit from the ECT Sensor and IAT Sensor to the PCM harness connector.
- Measure the resistance of the Sensor ground circuit from the AAT Sensor harness connector to the BCM harness connector.
Is the resistance above 5.0 Ohms?
Yes
- Repair the excessive resistance in the Sensor ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 9
- CHECK THE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between ground and the Sensor Signal circuit at the Sensor harness connector.
Is the resistance below 100 Ohms?
Yes
- Repair the short to ground in the Sensor Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 7
- Measure the resistance between ground and the Sensor Signal circuit at the Sensor harness connector.
- CHECK FOR THE SENSOR SIGNAL CIRCUIT SHORTED TO THE SENSOR GROUND CIRCUIT
- Measure the resistance between ground and the Sensor Signal circuit at the Sensor harness connector.
Is the resistance below 100 Ohms?
Yes
- Repair the short between the Sensor ground circuit and the Sensor Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 8
- Measure the resistance between ground and the Sensor Signal circuit at the Sensor harness connector.
- CHECK THE SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
- Turn the ignition on.
- Measure the voltage on the Sensor Signal circuit at the Sensor harness connector.
Is there any voltage present?
Yes
- Repair the short to voltage in the Sensor Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 9
- POWERTRAIN CONTROL MODULE (PCM)
- Turn the ignition off.
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the related Sensors and the Powertrain Control Module (PCM).
- Look for any chafed, pierced, pinched or partially broken wires.
- 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.
- 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.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .