On-Vehicle

IDLE AIR CONTROL (IAC) VALVE ON-VEHICLE INSPECTION

1. Inspect IAC valve operation.
(a) Initial conditions:
- Engine at normal operating temperature
- Idle speed checked correctly
- Transmission in neutral position
- A/C switch OFF





(b) Using SST, connect terminals TE1 and E1 of the DLC1. SST 09843-18020
(c) After engine speed is kept at approx. 1,000 rpm for 5 seconds, check that it returns to idle speed.
If the engine speed operation is not as specified, check the IAC valve, wiring and ECM.
(d) Remove the SST from the DLC1. SST 09843-18020
2. Inspect IAC valve resistance.

NOTICE: "Cold" and "Hot" in the following sentences express the temperature of the coils themselves. "Cold" is from -10°C (14°F) to 50°C (122°F) and "Hot" is from 50°C (122°F) to 100°C (212°F).

(a) Disconnect the IAC valve connector.





(b) Using an ohmmeter, measure the resistance between terminal +B and other terminals (RSC, RSO).

Resistance:
Cold: 17.0 - 24.5 ohm
Hot: 21.5-28.5 ohm

If resistance is not as specified, replace the IAC valve.
(c) Reconnect the IAC valve connector.
3. Inspect air assist system.
(a) Initial conditions:
- Engine at normal operating temperature
- Idle speed checked correctly
- Transmission in neutral position
- A/C switch OFF





(b) Using SST connect terminals TE1 and E1 of the DLC1. SST 09843-18020
(c) After engine speed is kept at 900 - 1,300 rpm for 10 seconds, check that it returns to idle speed.
(d) stop the engine





(e) Disconnect the air assist hose from the air pipe, and block off the IAC valve exit and the entry to the pipe.
(f) Start the engine and check that the idle speed reaches 500 rpm or below (the engine may stall).
If the idle does not reach 500 rpm or below, check for a leak between the air assist hoses, pipe and injectors.
(g) Remove the SST from the DLC1. SST 09843-18020
(h) Reconnect the air assist hose to the IAC valve.