Idle Speed Control (ISC) Valve
- 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 |