Idle Speed Control (ISC) Valve
WARNING: This page is about a different car, the 1987 Toyota Supra. However, it is still accessible from the selected car via links, so may be relevant.
- Measure resistance between "B1" terminal and "S1" or "S" terminal, Also measure resistance between "B2" terminal and "S2" or "S4" terminal. If resistance is not as specified in table, replace ISC valve.
- Apply battery voltage to terminal "B1" and terminal "B2" while repeatedly grounding terminals "S1", "S2", "S", "S4" and "S1" in sequence to cause valve to close. See Fig 1.
- Apply battery voltage to terminals "B1" and "B2" while repeatedly grounding terminals "S4", "S", "S2", "S1" and "S4" in sequence to cause valve to open. Replace valve if not operating properly.
ISC VALVE RESISTANCE SPECIFICATIONS
| Terminals | Ohms |
|---|---|
| B1 - S1 Or S | 10-30 |
| B2 - S2 Or S4 | 10-30 |