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 Tracker Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Diagnostic Circuit Check
NOTE:
Test numbers refer to test numbers on diagnostic chart.
The Diagnostic Circuit Check is a starting point to identifying a problem caused by the fuel injection system.
- If "CHECK ENGINE" light illuminates with ignition on and engine stopped, this confirms battery and ignition voltage to the ECM.
- The ECM will flash Code 12 with the "CHECK ENGINE" light. This indicates ECM diagnostics are working. Code 12 will not flash 3 times if other codes are stored in memory. Each additional code will flash 3 times. Codes will start with the lowest code. If no codes are present, Code 12 will flash until fuse is removed from fuse box.
- Record all codes stored except Code 12. If vehicle problem is engine cranks but will not run, see BASIC TESTING article.
- If no additional codes were recorded, refer to TESTS W/O CODES article.
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.