Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Test
- ACTIVE DTC NOTE:
Diagnose and repair any O2 Sensor or fuel system related DTCs before proceeding with this diagnostic procedure.
- Start the engine and allow it to reach operating temperature.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.
- Test drive the vehicle according to the monitoring conditions.
- With a scan tool, select View DTCs.
Is the status Active for this DTC?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic Procedure. Refer to INTERMITTENT CONDITION .
- Start the engine and allow it to reach operating temperature.
- CHECKING THE EXHAUST SYSTEM FOR LEAKS
- Turn the ignition off.
- Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS diagnostic procedure. Refer to DIAGNOSIS AND TESTING
.
Were any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 3
- CHECK THE FUEL SYSTEM
- Check the entire fuel system for high fuel pressure, excessive fuel volume, or leaking Fuel Injectors. Refer to DIAGNOSIS AND TESTING
.
Were any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 4
- Check the entire fuel system for high fuel pressure, excessive fuel volume, or leaking Fuel Injectors. Refer to DIAGNOSIS AND TESTING
.
- O2 SENSOR
- Replace the O2 Sensor.
- Turn the ignition on.
- With the scan tool, erase DTCs.
- Start the engine and allow it to reach operating temperature.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.
- Test drive the vehicle according to the monitoring conditions.
- With a scan tool, select View DTCs.
Did the DTC return?
Yes
- Go To 5
No
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- POWERTRAIN CONTROL MODULE (PCM)
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the 1/2 O2 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.
- Refer to any Technical Service Bulletins that may apply.
Were 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 .
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.