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.
  NOTE:
  Low battery voltage can also cause excessive current draw, in very hot and very cold ambient temperatures. Make sure the battery can pass a load test before continuing.
2. Start the engine.
3. Allow the engine to reach normal operating temperature.
4. With a 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?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
THROTTLE PLATE INSPECTION
1. Turn the ignition off.
2. Remove the Air Cleaner Assembly from the Throttle Body.
3. Check for any signs of a foreign material (ice, dirt, or excessive carbon build up) on the Throttle Plate or in the bore causing the Throttle Plate to stick.
  Were any signs of foreign material or scoring of the throttle plate or bore found?
  
  Yes
  - Remove the debris if possible or replace the Throttle Body Assembly if the debris cannot be removed. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the Throttle Body Self Learn.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 3
DIRTY AIR FILTER
1. Remove and inspect the Air Filter.
  Is the Air Filter dirty?
  
  Yes
  - Replace the Air Filter.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 4
CONTAMINATED FUEL
1. Inspect the Fuel for contamination. (Dirt, water, or other foreign material)
  Is the fuel contaminated?
  
  Yes
  - Drain the Fuel from the fuel tank into an approved gas holding tank and add clean fuel. Refer to DRAINING FUEL TANK .
  No
  - Go To 5
EXCESSIVE RESISTANCE IN THE ETC POSITIVE CIRCUIT
1. Turn the ignition off.
2. Using a voltmeter perform a voltage drop test. Back probe the ETC Positive circuit at the Throttle Body harness connector and probe the appropriate terminal of the PCM C2 harness connector. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.
  WARNING:
  When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
3. Start the engine and allow it to reach normal operating temperature.
4. Monitor the voltmeter.
  Is the voltage below 0.25 volts?
  
  Yes
  - Go To 6
  No
  - Repair the excessive resistance in the ETC Positive circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
EXCESSIVE RESISTANCE IN THE ETC NEGATIVE CIRCUIT
1. Turn the ignition off.
2. Move the voltmeter leads to back probe the ETC Negative circuit at the Throttle Body harness connector and to probe the appropriate terminal of the PCM C2 harness connector. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.
  WARNING:
  When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
3. Start the engine and allow it to reach normal operating temperature.
4. Monitor the voltmeter.
  Is the voltage below 0.25 volts?
  
  Yes
  - Go To 7
  No
  - Repair the excessive resistance in the ETC Negative circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
ETC MOTOR
1. Turn the ignition off.
2. Connect the Throttle Body harness connector.
3. Measure the resistance of the ETC Motor by probing the appropriate terminals of PCM C2 harness connector for the ETC Positive circuit and the ETC Negative circuit.
  Is the resistance between 2.5 and 25 Ohms at closed throttle?
  
  Yes
  - Go To 8
  No
  - Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module harness connectors. Replace the Throttle Body Assembly if no problems were found in the connectors. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the Throttle Body Self Learn.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body Assembly 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 Throttle Body and Powertrain Control Module harness connectors.
4. Perform any Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  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, 16V Turbo .