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.
1989 Geo Metro BaseFACTORY OEM SERVICE PROCEDURE
Chart A-1, No Check Engine Light: Notes
The CHECK ENGINE light should stay on when ignition switch is in ON position and engine is not running. The ECM turns on CHECK ENGINE light by completing a ground circuit.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- Completing a ground circuit should illuminate the CHECK ENGINE light.
- This checks for battery voltage from the control relay.
- This verifies battery voltage to control relay from ignition switch.
- This verifies a good ground circuit from ECM connector to ground.
- If test light illuminates, this indicates a faulty control relay.
Factory Service Tools
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.