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:

Terminals of ecu
1. Inspect tvip ecu Inspect the ecub, dome and ecuig fuses. disconnect the tvip ecu connector, and the continuity and voltage of check each terminal of the disconnected connector. Standard: If the result is not as specified, the vehicles side may malfunction. Reconnect ...

Inspection procedure
Hint Advanced timing over (valve timing is out of specified range) P0011 Retarded timing over (valve timing is out of specified range) P0012 If dtc p0011 or p0012 is displayed, check the vvt system circuit. Read freeze frame data using the handheld tester or ...

Ecm (1zzfe)
Replacement 1. Disconnect battery negative terminal 2. Remove glove compartment door assy 3. Remove ecm Remove the 2 clips using a clip remover. Then, open the cover. Disconnect the 4 ecm connectors.  remove the wire harness from the wire harness clamp. Remove the 2 ...

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