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. Start the engine and allow it to idle for at least 60 seconds.
  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.
2. With the scan tool, read DTCs.
  Is the DTC active?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
O2 SENSOR HEATER ELEMENT
1. Turn the ignition off.
  NOTE:
  Allow the O2 Sensor to cool down to room temperature.
2. Disconnect the O2 Sensor 1/1 harness connector.
3. Measure the resistance across the O2 Sensor 1/1 Heater element, between the Heater Control terminal and the Heater ground terminal at the O2 Sensor (component side).
  NOTE:
  O2 Sensor 1/1 Heater Element resistance values should be measured at 21.1°C (70°F). The resistance value will vary with different temperature values.
  
  Is the O2 Sensor 1/1 Heater Element resistance between 2.0 and 30.0 Ohms?
  
  Yes
  - Go To 3
  No
  - Verify that there is good pin to terminal contact in the O2 Sensor and Powertrain Control Module connectors. If OK, replace the O2 Sensor. Refer to SENSOR, OXYGEN, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
CHECK THE (K79) O2 SENSOR 1/1 HEATER CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Disconnect the PCM C1 harness connector.
2. Check for continuity between ground and the (K79) O2 Sensor 1/1 Heater Control circuit at the O2 Sensor harness connector.
  Is there continuity between ground and the (K79) O2 Sensor 1/1 Heater Control circuit?
  
  Yes
  - Repair the (K79) O2 Sensor 1/1 Heater Control circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 4
CHECK THE (K79) O2 SENSOR 1/1 HEATER CONTROL CIRCUIT FOR AN OPEN
1. Measure the resistance of the (K79) O2 Sensor 1/1 Heater Control circuit between the O2 Sensor harness connector and the PCM C1 harness connector.
  Is the resistance below 0.5 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (K79) O2 Sensor 1/1 Heater Control circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
EXCESSIVE RESISTANCE IN THE ASD RELAY (F344) FUSED ASD RELAY OUTPUT CIRCUIT
1. Measure the resistance of the ASD Relay (F344) Fused ASD Relay Output circuit between the O2 Sensor harness connector and the ASD Relay Output terminal.
  Is the resistance below 0.5 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the excessive resistance in the (F344) Fused ASD Relay Output circuit.
  - 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 Oxygen Sensor 1/1 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 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 .