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.
1994 Geo Metro XFiFACTORY OEM SERVICE PROCEDURE
Engine Controls - Tests W/Codes
- Introduction
- Self-Diagnostic System
- Diagnostic Code Charts (Standard Emissions)
- Notes
- On-Board Diagnostic (OBD) System Check (Standard Emissions)
- Chart A1-1 (Standard Emissions) - No Malfunction Indicator (Mil) On Steady
- Chart A1-2 (Standard Emissions) - Won't Flash Any Codes, Or (Mil) On Steady
- Code 13 (Standard Emissions) - Oxygen Sensor, Signal Voltage Does Not Change
- Code 14 (Standard Emissions) - Engine Coolant Temperature Sensor, Low Temperature Indicated
- Code 15 (Standard Emissions) - Engine Coolant Temperature Sensor, High Temperature Indicated
- Code 21 (Standard Emissions) - Throttle Position (TP) Sensor, Signal Voltage High
- Code 22 (Standard Emissions) - Throttle Position (TP) Sensor, Signal Voltage Low
- Code 23 (Standard Emissions) - Intake Air Temperature Sensor, Low Temperature Indicated
- Code 24 (Standard Emissions) - Vehicle Speed Sensor
- Code 25 (Standard Emissions) - Intake Air Temperature Sensor, High Temperature Indicated
- Code 31 (Standard Emissions) - Manifold Absolute Pressure Sensor, Low Voltage - Low Vacuum
- Code 32 (Standard Emissions) - Manifold Absolute Pressure Sensor, High Voltage - High Vacuum
- Code 41 (Standard Emissions) - Ignition Signal Circuit
- Code 42 (Standard Emissions) - Camshaft Position Sensor Circuit, No Signal For 2 Seconds
- Code 51 (Standard Emissions) - Exhaust Gas RECIRCULATION
- Diagnostic Code Charts (Upgraded Emissions)
- Notes
- On-Board Diagnostic (OBD) System Check (Upgraded Emissions)
- Chart A2-1 (Upgraded Emissions) - No Malfunction Indicator Light (Mil)
- Chart A2-2 (Upgraded Emissions) - Won't Flash Any Codes, Or (Mil) On Steady
- Code 13 (Upgraded Emissions) - Heated Oxygen Sensor, Signal Voltage Does Not Change
- Code 14 (Upgraded Emissions) - Engine Coolant Temperature Sensor, Low Temperature Indicated
- Code 15 (Upgraded Emissions) - Engine Coolant Temperature Sensor, High Temperature Indicated
- Code 21 (Upgraded Emissions) - Throttle Position Sensor, Signal Voltage High
- Code 22 (Upgraded Emissions) - Throttle Position Sensor, Signal Voltage Low
- Code 23 (Upgraded Emissions) - Intake Air Temperature Sensor, Low Temperature Indicated
- Code 24 (Upgraded Emissions) - Vehicle Speed Sensor
- Code 25 (Upgraded Emissions) - Intake Air Temperature Sensor, High Temperature Indicated
- Code 31 (Upgraded Emissions) - Manifold Absolute Pressure Sensor, Low Voltage - Low Vacuum
- Code 32 (Upgraded Emissions) - Manifold Absolute Pressure Sensor, High Voltage - High Vacuum
- Code 41 (Upgraded Emissions) - No Ignition Signal
- Code 42 (Upgraded Emissions) - Camshaft Position Sensor, No Signal For 2 Seconds
- Code 46, (Upgraded Emissions) - Idle Speed Control Motor
- Code 51 (Upgraded Emissions) - Exhaust Gas RECIRCULATION
- 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.