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.
1990 Geo Storm GSi, StandardFACTORY OEM SERVICE PROCEDURE
Engine Controls - System/Component Tests
- Introduction
- Air Induction Systems
- Computerized Engine Controls
- Engine Sensors & Switches
- Engine Controls - System/Component Tests
- Coolant Temperature Sensor (Prizm & Prizm GSi)
- Coolant Temperature Sensor (All Except Prizm & Prizm GSi)
- EGR Temperature Sensor (Tracker - Calif. Only)
- Knock Sensor (Prizm GSi)
- Gear Position Switch (5th Gear M/T Tracker)
- Manifold Absolute Pressure (MAP) Sensor (Metro, Prizm, Storm, Storm GSi & Tracker)
- Mass Airflow (MAF) Sensor (Prizm GSi)
- Manifold Air Temperature (MAT) Sensor (Metro, Storm, Storm GSi & Tracker)
- Manifold Air Temperature (MAT) Sensor (Prizm & Prizm GSi)
- Oxygen Sensor (All Models)
- Sub-Oxygen Sensor (Prizm GSi - Calif. Only)
- Power Steering Pressure Switch (Storm & Storm GSi)
- Power Steering Pressure Switch (Tracker)
- Throttle Position Sensor (Except Metro M/T & Prizm VIN 6)
- Throttle Position Switch (Metro M/T & Prizm 4A-FE VIN 6)
- Park/Neutral Switch (Metro)
- Park/Neutral Switch (Storm 3-Speed)
- Park/Neutral Switch (Storm GSi 4-Speed)
- Park/Neutral Switch (Prizm & Prizm GSi)
- Park/Neutral Switch (Tracker)
- Vehicle Speed Sensor (Metro)
- Vehicle Speed Sensor (Prizm & Prizm GSi)
- Vehicle Speed Sensor ECU Code 24 (Storm & Storm GSi)
- Vehicle Speed Sensor ECU Code 24 (Storm GSi)
- Vehicle Speed Sensor ECU Code 11 (Storm GSi)
- Engine Controls - System/Component Tests
- Relays & Solenoids
- Fuel System
- Idle Control System
- Engine Controls - System/Component Tests
- Air Valve (Metro)
- Idle Air Valve (Prizm & Prism GSi)
- Air Valve (Tracker)
- Idle Air Control (IAC) Valve (Storm & Storm GSi)
- Idle Speed Control Solenoid (Metro)
- Idle Speed Control Solenoid Function Test (Tracker)
- Idle Speed Control Solenoid (Tracker)
- Idle Speed Control Solenoid Valve (Prizm)
- Idle-Up Vacuum Switching Valve (IVSV) (Prism GSi)
- Throttle Opener Vacuum Switching Valve (VSV) (Tracker)
- Engine Controls - System/Component Tests
- Chart C-2C Idle Air Control (IAC) (Storm)
- Ignition System
- Timing Control Systems
- Emission Systems & Sub-Systems
- Exhaust Gas RECIRCULATION
- Fuel Evaporation
- Charcoal Canister Check Valve (Metro)
- Charcoal Canister Check Valve (Prizm & Prizm GSi)
- Fuel Evaporation Canister (Storm & Storm GSi)
- Fuel Evaporation Canister (Tracker)
- Fuel Evaporation Bimetallic Vacuum Switching Valve (BVSV) (Metro)
- Fuel Evaporation Bimetallic Vacuum Switching Valve (BVSV) (Prizm & Prizm GSi)
- 2-Way Valve Check (Metro & Tracker)
- PCV
- Positive Temperature Coefficient (PTC) Heater
- Miscellaneous Controls
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.