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.
Vacuum Switching Valve (8R-C)
Measure resistance of magnetic coil. Measure resistance between (+) and TP, resistance should be 18.7 ohms. Measure resistance between (+) and T.C.S., resistance should be 28 ohms. Disconnect wiring and remove switching valve from vehicle. Blow air into each passage and inspect operation of each valve. Check for defects in wiring connections. Replace vacuum switching valve assembly if defect is not in wiring. Check valves as follows:
- In "OFF" position air should pass from "A" to "F", "B" to "E", and from "D" to "G".
- In "ON" position (TP off), air should pass from "A" to "G", "B" to "E", and "D" to "F".
- In "ON" position (TP on), air should pass from "A", "C", "E" and "G" in any combination of directions. Air should also be able to pass from "D" to "F".
- In "OFF" position (TP on), air should pass from "A", "C" and "E" in any combination of directions. Air should also be able to pass from "B" to "F" and from "D" to "G".
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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.