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.
Pcm Code E043, Left Oxygen (O2) Sensor Rich Signal: Action
PCM turns on SERVICE ENGINE SOON light. PCM turns on canister purge solenoid.
- With O2 sensor disconnected, parameter ED32 should remain at reference voltage (.38-.63 volt).
- Checks O2 sensor circuitry ability to record lean readings.
- PCM compares O2 sensor signal voltage received on circuit No. 1589 to ground voltage on circuit No. 413. If PCM does not have a good ground to engine on circuit No. 413, O2 sensor can appear falsely high or low. With engine running, use a voltmeter to measure voltage between O2 sensor at exhaust manifold and PCM terminal B6. If voltage is -.05 to +.05 volt, ground is okay. If voltage is less than -.05 volt or greater than +.05 volt, repair poor ground on circuit No. 413 between PCM terminal B6 and ground at front of engine on right cylinder head.
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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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