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
- CHECK FOR ANY SERVICE BULLETINS OR PCM SOFTWARE UPDATES
- Check for any applicable Service Bulletins or Flash updates related to the DTC.
Are there any applicable Service Bulletins or Flash updates?
Yes
- Perform the applicable repair.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 2
- Check for any applicable Service Bulletins or Flash updates related to the DTC.
- READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN
- With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
- For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
- With the scan tool, erase all DTCs.
- Turn the ignition off for a minimum of 10.0 seconds.
- Turn the ignition on.
- Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Go To 3
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
- CHECK FOR OTHER DTCS
- Refer to the recorded DTCs.
Are there any O2 Sensor circuit fault DTCs present?
Yes
- Perform the applicable diagnostic procedure(s). Refer to DIAGNOSTIC CODE INDEX, 5.7L .
No
- Go To 4
- Refer to the recorded DTCs.
- CHECKING THE EXHAUST SYSTEM FOR LEAKS
- Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS test procedure. Refer to CHECKING THE EXHAUST SYSTEM FOR LEAKS
.
Were any exhaust leaks found?
Yes
- Perform the appropriate repairs.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 5
- Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS test procedure. Refer to CHECKING THE EXHAUST SYSTEM FOR LEAKS
.
- CHECK THE O2 SENSOR 2/2 (K243) SIGNAL CIRCUIT VOLTAGE FOR BEING OUT OF RANGE
- Turn the ignition off
- Disconnect the O2 Sensor 2/2 harness connector.
- Turn the ignition on.
- Measure the voltage on the O2 Sensor 2/2 (K243) Signal circuit in the O2 Sensor 2/2 harness connector.
Is the voltage between 4.1 and 5.0 volts?
Yes
- Go To 6
No
- Check the O2 Sensor 2/2 (K243) Signal circuit for a short to ground, open, or short to voltage. If no problems are found, replace and program the Powertrain Control Module in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL AND INSTALLATION .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- CHECK THE (K904) SENSOR RETURN CIRCUIT VOLTAGE FOR BEING OUT OF RANGE
- Measure the voltage on the (K904) Sensor Return circuit in the O2 Sensor 2/2 harness connector.
Is the voltage at 2.5 volts?
Yes
- Go To 7
No
- Check the (K904) Sensor Return circuit for a short to ground, open, or short to voltage. If no problems are found, replace and program the Powertrain Control Module in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL AND INSTALLATION .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the voltage on the (K904) Sensor Return circuit in the O2 Sensor 2/2 harness connector.
- CHECK THE O2 SENSOR WIRING HARNESS AND CONNECTOR FOR DAMAGE OR POOR FIT NOTE:
Check for signs of contaminants that may have damaged the O2 Sensor, such as contaminated fuel, unapproved silicone, oil and coolant.
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the O2 Sensor 2/2 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 O2 Sensor 2/2 and Powertrain Control Module connectors.
- Perform any 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 the Oxygen Sensor 2/2 in accordance with the Service Information. Refer to OXYGEN SENSOR .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the O2 Sensor 2/2 and the Powertrain Control Module (PCM).
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.