Idle Speed Control System: Notes
- Before idle speed/IAC duty is checked or adjusted, ensure all wires and vacuum hoses are connected securely, accelerator cable has some play, valve clearance and timing are set to specification and all accessories are turned off. Ensure transmission is in "P" (A/T) or "N" (M/T), battery voltage is greater than 11 volts and throttle valve moves smoothly.
- Warm engine to normal operating temperature. Connect tachometer. Using a jumper wire, connect monitor connector terminal "D" (ground) to terminal "B" (diagnostic switch). Ensure Malfunction Indicator Light (MIL) indicates a Code 12. Connect duty meter between terminal "D" (ground) and terminal "F" (duty output). See Fig 1 .
- Ensure ISC duty varies in accordance with engine load. See the ISC DUTY SPECIFICATION table. Turn ignition off and allow engine to cool. Ensure ISC actuator moves when ignition is turned on. If plunger does not move and ISC duty are not within specification, check wiring and related components.
ISC DUTY SPECIFICATION
| Engine Load | ISC Duty Increase Percentage |
|---|---|
| Electrical Load | About 3.5 |
| Radiator Fan | About 3.5 |
| A/C | About 10 |
NOTE:
DO NOT
remove ISC actuator from throttle body, it is adjusted by manufacturer.