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 Tracker L4-1590cc 1.6LFACTORY OEM SERVICE PROCEDURE
Throttle Position Sensor
THROTTLE POSITION SENSOR:
Checking Throttle Position Sensor:
RESISTANCE BETWEEN "C" AND "D" TERMINALS (IDLE SWITCH):
Throttle valve at idle position 0-500 Ohms
Throttle valve wide open Infinity
RESISTANCE BETWEEN "A" AND "D" TERMINALS:
All conditions 3.5-6.5K Ohms
RESISTANCE BETWEEN "B" AND "D" TERMINALS:
Throttle valve at idle position 2.0-6.5K Ohms
NOTE:
1. To move throttle valve to idle position apply 30" Hg vacuum to throttle opener.
2. There should be more than 2K ohms resistance difference between when throttle is at idle position and when it is fully open.
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.