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.

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HOMESERVICE MANUALSTOYOTA1986PICKUP BASE, 22-RTE, R151FREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMTCCS SYSTEMDIAGNOSIS & TESTINGCOMPONENT TESTINGIDLE SPEED CONTROL (ISC) VALVE

1986 Toyota Pickup Base, 22-RTE, R151F

Idle Speed Control (ISC) Valve

1986 Toyota Pickup Base, 22-RTE, R151FSECTION Idle Speed Control (ISC) Valve

After stopping engine, clicking sound should be heard from ISC valve. If not, remove ISC valve and perform operation check.
Drain engine coolant. Disconnect 2 electrical connectors, 2 coolant by-pass hoses and air hoses. Remove 2 bolts and ISC valve body.
Apply battery voltage to dual-terminal connector. Grounding terminals S1, S2, S and S4 in sequence should cause valve to close. See Fig 1. With battery voltage still connected, grounding terminals in reverse sequence (S4, S, S2 and S1) should cause valve to open. If not, perform resistance check.

Fig 1: Checking ISC Valve Operation Valve should open when voltage is applied in one direction and close when voltage is applied in reverse direction.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Check resistance values of ISC valve. Check resistance with ignition off and ISC electrical connector disconnected. If resistance is not as specified in chart, replace ISC valve.

ISC VALVE RESISTANCE SPECIFICATIONS

Terminals	Ohms
B1 - S1 or S	10-30
B2 - S2 or S4	10-30

RENDER: 1.0x

NO RELATED

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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.