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.
System Readiness Test Codes: Notes
If battery has been disconnected, DTCs have been cleared or ECM/PCM has been reset, readiness codes will reset. In some states part of emission testing is to ensure readiness codes are complete. If readiness codes are not complete, emission test cannot be finished.
To check if readiness codes are complete, turn ignition switch on, engine off. MIL will illuminate for 2 seconds. If MIL goes off, readiness codes are complete. If MIL blinks several times, one or more readiness codes are not complete.
To set each code, drive vehicle or run engine as described in following procedures.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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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