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.
1993 Geo Storm Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Engine Controls - Tests W/Codes
- Introduction
- Self-Diagnostic System
- Diagnostic Code Charts
- Notes
- Diagnostic Circuit Check
- Chart A-1, Won't Flash Code 12, No Mil
- Chart A-2, No DLC Data Or Won't Flash Code 12, Mil On Steady
- Code 13, Non-Heated Oxygen (O2) Sensor CTK, Open CKT (VIN 6)
- Code 13, Heated O2 Sensor Circuit, Open Circuit (VIN 8)
- Code 14, ECT Circuit High/Low Temperature Indicated
- CODE 21, TP SENSOR CIRCUIT, SIGNAL VOLTAGE HIGH/LOW (1 Of 2)
- Code 21, TP Sensor Circuit, Signal Voltage High/Low (2 Of 2)
- Code 23, IAT Sensor Circuit, High/Low Temperature Indicated
- Code 24, Vehicle Speed Sensor (VSS) Circuit
- Code 32, EGR System Error (CALIF. Only)
- CODE 33, MAP SENS CKT, SIGNAL VOLT HIGH/LOW - LOW/HIGH VACUUM (1 Of 2)
- CODE 33, MAP SENS CKT, SIGNAL VOLT HIGH/LOW - LOW/HIGH VACUUM (2 Of 2)
- Code 42, Ignition Control (Ic) Circuit Error
- Code 44, Non-Heated O2 Sens CKT, Lean Exhaust INDC'T (VIN 6)
- Code 44, Heated O2 Sens CKT, Lean Exhaust Indicated (VIN 8)
- Code 45, Non-Heated O2 Sens CKT, Rich Exhaust Indicated
- Code 45, Heated O2 Sens CKT, Rich Exhaust Indicated (VIN 8)
- Code 51, ECM Failure, ECM Failed Or EEPROM Failure
- Summary
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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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