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:
- If MIL/CHECK ENGINE light is on, service diagnostic trouble codes in order retrieved. See DIAGNOSTIC TROUBLE CODE REFERENCE CHART.
- If Continuous Memory Code 215, 216, 217, 218, 222, 224, 232 or 238 is retrieved during KOEO SELF-TEST, see IGNITION SYSTEM in the SYSTEM/COMPONENT TESTS - EEC-IV (2.0L) article.
- If vehicle has a no-start condition, go to CIRCUIT TEST AA (DI), CIRCUIT TEST AB (EI - low data rate) or CIRCUIT TEST AC (EI - high data rate).
- If vehicle displays a Code 111 (pass code) and does not have any symptoms described in previous steps, go to KOER SELF -TEST.
Use the Manual With the Right Hardware
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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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