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.
KOEO Self-Test
Ensure engine is warmed to normal operating temperature. If engine does not start (or stalls after starting), continue KOEO SELF-TEST. DO NOT depress throttle. Turn ignition off. Ensure test equipment is properly attached. Turn ignition on (engine off). Record all KOEO and Continuous Memory Codes.
If a Code 111 (pass code) is not retrieved, service KOEO codes. See DIAGNOSTIC TROUBLE CODE REFERENCE CHART . If PCM will not output codes, go to CIRCUIT TEST QA. If diagnostic trouble codes are retrieved, perform the following:
- If Malfunction Indicator Light (MIL) is on, service diagnostic trouble codes in order retrieved. See DIAGNOSTIC TROUBLE CODE REFERENCE CHART .
- If vehicle has a no-start condition, go to CIRCUIT TEST AA.
- If vehicle displays Code 111 (pass code) and does not have any symptoms described in previous steps, go to KOER SELF-TEST.
NO RELATED
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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.