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.
Possible Causes
| Possible Causes |
|---|
| (K41) O2 1/1 SIGNAL CIRCUIT SHORTED TO VOLTAGE |
| (K902) O2 RETURN UPSTREAM CIRCUIT SHORTED TO VOLTAGE |
| (K41) O2 1/1 SIGNAL CIRCUIT OPEN |
| (K902) O2 RETURN UPSTREAM CIRCUIT OPEN |
| 1/1 O2 SENSOR |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding.
Use the Manual With the Right Hardware
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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.
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