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.
1988 Toyota Land CruiserFACTORY OEM SERVICE PROCEDURE
Idle Speed Control (ISC) Valve
- Listen for "clicking" sound after engine is shut off. If no sound is heard, disconnect ISC valve connector.
- Note terminal identification. Using an ohmmeter, check resistance between designated terminals. See ISC VALVE RESISTANCE SPECIFICATIONS table.ISC VALVE RESISTANCE SPECIFICATIONS
Terminals Ohms B1 - S1 or S 10-30 B2 - S2 or S4 10-30 - To check valve operation, apply battery voltage to terminal "B1" and terminal "B2". See Figure. Repeatedly ground terminals "S1", "S2", "S", "S4" and "S1" in sequence. Note that valve closes.
- Apply battery voltage to terminals "B1" and "B2". Repeatedly ground terminals "S4", "S", "S2", "S1" and "S4" in sequence. Note that valve opens. Replace valve if it failed to operate properly.
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.