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 Prizm Base, StandardFACTORY OEM SERVICE PROCEDURE
Function Test (Tracker)
- Warm engine to normal operating temperature and monitor engine RPM. With engine idling, turn headlights and blower fan on. Idle speed should increase, or at least be maintained at previous level. If so, system is functioning properly. If not, check electrical load signals to control unit.
- If electrical load signals are okay, check ISC solenoid. If solenoid is okay, check harness between ISC solenoid and control unit. If harness is okay, control unit is defective.
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.