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.
Self-Diagnostic System: Notes
Self-diagnostic system, if properly used, can simplify testing. PCM monitors several different engine control system circuits.
If a problem is sensed in a monitored circuit, fault code will be stored in PCM and MIL will come on, provided specific criteria are met. PCM will then enter limp-in mode, substituting information from other sources to compensate for component failure. Vehicle is operational in limp-in mode, but driveability may not be optimal.
A specific fault code results from a particular system failure. Fault code only indicates problem circuit. It does not identify specific component failure in the circuit.
If problem is repaired or ceases to exist, PCM automatically clears fault code after 50 ignition on-off cycles . Fault codes can also be cleared using DRB. See the ERASING FAULT CODES procedure under ON-BOARD DIAGNOSTICS .
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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.