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 Prizm Base, StandardFACTORY OEM SERVICE PROCEDURE
Camshaft Position Sensor
- Ensure ignition is off. Remove rotor from distributor housing. Remove ignition coil dust cover and gasket from distributor housing. Remove 2 nuts and 4 wires from ignition coil terminals.
- Remove 3 screws and 3 wires from igniter terminals. Remove 2 screws and igniter from distributor housing. Remove 2 connectors from harness retainer. Remove distributor wire from housing. Remove screw and noise suppressor condenser from housing.
- Using ohmmeter, measure resistance of distributor connector C1, when cold (14-104°F; -10-50°C), between terminals No. 3 and 6. See Fig 1 . Camshaft Position (CMP) sensor resistance should be 185-275 ohms. If resistance is not as specified, replace distributor housing.
- Measure resistance of distributor connector C1, when cold, between terminals No. 2 and 5. CMP sensor resistance should be 370-550 ohms. If resistance is not as specified, replace distributor housing.
- Measure resistance of distributor connector C1, when hot (104-212°F; 50-100°C), between terminals No. 3 and 6. CMP sensor resistance should be 240-325 ohms. If resistance is not as specified, replace distributor housing.
- Measure resistance of distributor connector C1, when hot, between terminals No. 2 and 5. CMP sensor resistance should be 475-650 ohms. If resistance is not as specified, replace distributor housing.
- Measure air gap between signal rotor and camshaft position sensor. Air gap should be .008-.016" (.2-.4 mm). If air gap is not as specified, replace distributor housing. When testing is complete, reverse disassembly procedure.
Factory Service Tools
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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.