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.
Code P048, EGR System Fault: Notes
To perform test, PCM turns off EGR flow to engine and monitors oxygen sensor (closed loop) integrator. With EGR off, integrator should swing to a greater value, reflecting leaner air/fuel mixtures. If integrator does not swing to a greater value, PCM assumes either EGR was turned off before test started or EGR is flowing and PCM does not have ability to turn it off. PCM monitors EGR 5 times in a given key cycle. If EGR does not respond 3 or more times during a key cycle, Code P048 is set.
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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.