Tacoma Extra Cab 2WD L4-2.4L (2RZ-FE) (1999)
Idle Air Control Valve: Component Tests and General Diagnostics
Component Inspection
1. INSPECT IAC VALVE RESISTANCE
NOTE: "Cold" end "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).
Using an ohmmeter, measure the resistance between terminal +B and other terminals (RSC, RSO).
Resistance:
Cold: 17.0 - 24.5 ohms
Hot: 21.5 - 28.5 ohms
If resistance is not as specified, replace the IAC valve
2. INSPECT IAC VALVE OPERATION
a. Connect the positive (+) lead from the battery to terminal +B and negative (-) lead to terminal RSC, and check that the valve is closed.
b. Connect the positive (+) lead from the battery to terminal +B and negative (-) lead to terminal RSO, and check that the valve is open.
On-Vehicle Inspection
INSPECT IAC VALVE OPERATION
a. Initial conditions:
-
Engine at normal operating temperature
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Idle speed checked correctly
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Transmission in neutral position