Toyota Tacoma manuals

Toyota Corolla Repair Manual: Circuit description

The rotary solenoid type idle air control (iac) valve is located

The rotary solenoid type idle air control (iac) valve is located under the throttle body and intake air bypassing the throttle valve flows into the iac valve through the passage.

In this way the intake air volume bypassing the throttle valve is regulated, controls the engine speed.

The ecm operates the iac valve only to perform idleup and provide feedback for the target idling speed.

Monitor description

Monitor description

The idle speeds are determined depending on the volume of air that passes

The idle speeds are determined depending on the volume of air that passes through the iac valve. When the volume is large, the idle speed becomes higher. When the volume is small, the idle speed becomes lower.

The iac valve controls the air volume that bypasses the throttle valve. The engine control module (ecm) sends duty signals to the iac valve and drives the iac valve stepper motor to determine the air volume that bypasses the throttle valve.

Although the ecm regulates the idle engine rpm with the feedback control in several vehicle stopped, actual idle rpm does not reach the targeted rpm and a learned valve angle of the idle air control (iac) remains at the maximum or remains at the minimum, the ecm determines to detect malfunction in the iac system.

Example: if the rpm difference between the targeted and actual idle engine rpms exceeds 200 rpm (*1) with the vehicle stopped in an idle, and this occurs 5 times, or if the learned value angle of the iac remains at its maximum or minimum angle for 5 seconds, p505 is detected.

P0511 is detected as an open/short circuit in the iac if the rate of duty signal input to the iac valve has stuck at 0 or 100 %.

*1: Threshold rpm is varied by an engine load.

Monitor strategy

Typical enabling condition

Typical enabling condition

Typical malfunction thresholds

Typical malfunction thresholds

Component operating range

Component operating range

Wiring diagram

Wiring diagram

Inspection procedure

Idle air control System/ Circuit
Dtc p0505 idle air control system Dtc p0511 idle air control circuit ...

Inspection procedure
Hint: when the throttle position is slightly opened (the accelerator pedal is slightly depressed) because a floor carpet is overlapped on the accelerator pedal, or if not fully releasing t ...

Other materials:

Inspection
1. Spark plug Notice: never use a wire brush for cleaning. Never attempt to adjust the electrode gap on used spark plug. Spark plug should be replaced every 192,000 km (120,000 miles). Clean the spark plugs. Air pressure: below 588 kpa (6.0 Kg/cm2, 85 psi) duration: 20 sec ...

Using the steering wheel switches
The steering wheel switches can be used to operate a connected cellular phone. Operating a telephone using the steering wheel switches ■ Steering wheel switches on the right hand side 1 Off hook switch Make a call Receive a call Display Phone screen 2 On hook switch End a cal ...

Precheck
1. Srs warning light check Turn the ignition switch to the on position and check that the srs warning light lights up. check that the srs warning light goes out after approx. 6 Seconds. Hint: when the ignition switch is at on and the srs warning light remains on or flashes, the ...

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