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:
A new downstream O2 Sensor along with an aging upstream O2 Sensor may cause the DTC to set. Review the repair history of the vehicle before continuing.

NOTE:
If an O2 Sensor DTC set along with the Catalytic Converter Efficiency DTC diagnose the O2 Sensor DTCs before continuing.

NOTE:
Check for contaminants that may have damaged the O2 Sensor and Catalytic Converter: contaminated fuel, unapproved silicone, oil and coolant, repair necessary.
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 .
VISUALLY INSPECT CATALYTIC CONVERTER
1. Inspect the Catalytic Converter for the following damage:
  - Damaged Catalytic Converter, dents or holes.
  - Severe discoloration caused by overheating the Catalytic Converter.
  - Catalytic Converter broke internally.
  - Inspect both ends of the converter, inlet and outlet.
  - Leaking Catalytic Converter.
  Were any problems found?
  
  Yes
  - Replace the Catalytic Converter. Repair the condition that may have caused the failure.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V .
  No
  - Go To 3
CHECKING THE OXYGEN SENSOR OPERATION
1. Perform the CHECKING THE OXYGEN SENSOR OPERATION diagnostic procedure. Refer to DIAGNOSIS AND TESTING .
  Does the Oxygen Sensor operate as described?
  
  Yes
  - Go To 4
  No
  - Go To 5
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Sensor 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 Sensor and the Powertrain Control Module harness 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, 16V .
  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, 16V .
CHECKING THE EXHAUST SYSTEM FOR LEAKS
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.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V .
  No
  - Go To 6
ENGINE MECHANICAL CONDITION
1. Check the exhaust for excessive smoke caused by an internal problem in the engine.
  Is an engine mechanical condition present?
  
  Yes
  - Repair the engine mechanical condition as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V .
  No
  - Go To 7
AGING O2 SENSOR
1. A new rear O2 sensor along with an aging front O2 sensor may cause the DTC to set.
2. Review the vehicles repair history.
  Has the rear O2 Sensor been replaced without replacing the front O2 Sensor?
  
  Yes
  - Replace the front O2 sensor as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V .
  No
  - Go To 8
CATALYTIC CONVERTER
If there are no possible cause remaining, view repair.

Repair
- Replace the Catalytic Converter.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V .