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 Spectrum 2D Hatchback, AutomaticFACTORY OEM SERVICE PROCEDURE
Throttle Position Sensor (TPS)/Idle Switch (Spectrum)
Connect an ohmmeter between TPS terminals "B" and "C". See Fig 1 . Resistance should steadily decrease as throttle is opened.
TPS RESISTANCE (TRACKER)
| Application | Resistance Ohms | |
|---|---|---|
| Between Terminals C-D | ||
| At Idle | 0-500 | |
| Wide Open Throttle | Infinite | |
| Between Terminals A-D | 3500-6500 | |
| Between Terminals B-D | ||
| At Idle | 0-2000 | |
| Wide Open Throttle | 2000-6500 | |
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.