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.
1991 Geo Metro LSi, 2D Hatchback, AutomaticFACTORY OEM SERVICE PROCEDURE
Engine Controls - Sensor Operating Range Charts: Introduction: Notes
Sensor operating range information can help determine if a sensor is out of calibration. An out-of-calibration sensor may not set a trouble code, but it may cause driveability problems.
NOTE:
Unless stated otherwise in test procedure, perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance.
COOLANT TEMPERATURE SENSOR RESISTANCE
| Temperature Β°F (Β°C) | Ohms |
|---|---|
| 0 (-18) | 14,650 |
| 20 (-7) | 8100 |
| 40 (4) | 4780 |
| 70 (21) | 2350 |
| 100 (38) | 1250 |
| 160 (71) | 400 |
| 210 (99) | 190 |
IAT SENSOR RESISTANCE
| Temperature Β°F (Β°C) | Ohms |
|---|---|
| 0 (-18) | 14,650 |
| 20 (-7) | 8100 |
| 40 (4) | 4780 |
| 70 (20) | 2350 |
| 100 (38) | 1250 |
| 160 (71) | 400 |
| 210 (99) | 190 |
THROTTLE POSITION SENSOR (TPS) RESISTANCE (A/T)
| Condition | Resistance (Ohms) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Between Terminals A & B (1) | Continuity | ||||||||
| Between Terminals A & B (2) | No Continuity | ||||||||
| Between Terminals A & B (3) | Continuity | ||||||||
| Between Terminals A & D (3) | 4370-8130 | ||||||||
| Between Terminals A & C (3) | 240-1140 | ||||||||
| Between Terminals A & C (4) | 3170-6600 | ||||||||
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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:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
