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.
1995 Geo Prizm Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Solenoid Test
NOTE:
Solenoid test should only be used when no DTCs are stored and a leaky solenoid or check valve is suspected.
- Turn ignition to LOCK position. Install Tech 1 with Mass Storage Cartridge (MSC). Turn ignition on, engine off. Pump brake pedal several times to deplete vacuum reserve. Select left front or right front motor release. Release motor on channel being tested. Select solenoid for the same channel.
- With no brake pressure applied, turn solenoid on. Depress brake pedal. If brake pedal is high and firm, go to next step. If brake pedal sinks to the floor, solenoid is leaking and not closing or check ball is leaking. Go to step 4).
- With brake pressure still applied, turn solenoid off. If brake pedal sinks to floor, solenoid operation is normal. If brake pedal does not sink to floor, go to next step.
- Ensure solenoid connectors are connected to correct solenoids (right front solenoid is on the rear of modulator, closest to brake power booster). If connections are incorrect, switch solenoid connectors, go to step 1) and repeat test. If connections are correct, switch solenoids, go to step 1) and repeat test. When second test is complete, go to next step.
- If channel works properly, test the other channel. If this channel fails test, replace solenoid currently installed in this channel. If test fails for the same channel, the check valve is leaking. Replace hydraulic modulator. When testing is complete, bleed hydraulic brake system. See BLEEDING BRAKE SYSTEM .
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.