P0508 Lexus Idle Air Control Valve Sense Circuit Low

P0508 Lexus Idle Air Control Valve Sense Circuit Low

Possible causes
– Dirty throttle body
– Electric throttle control actuator misadjusted or damaged
– Faulty Electric throttle control actuator
– Intake air leak
– Poor electrical connection to the Intake Air Control (IAC) valve
Tech description
If there are no intake leaks, clean throttle body, adjust engine idle and erase engine code. If the code comes back you may have to replaced the Electric Throttle Control Actuator (Motor) to repair the problem.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Engine hard to start
– Rough or erratic idle speed
P0508 Lexus Description

The Engine Control Module (ECM) controls the engine idle speed to a specified level through the fine adjustment of the air, which is let into the intake manifold, by operating the electric throttle control actuator. The operating of the throttle valve is varied to allow for optimum control of the engine idling speed. The ECM calculates the actual engine speed from signals of crankshaft position sensor (POS) and camshaft position sensor.

The ECM controls the electric throttle control actuator so that the engine speed coincides with the target value memorized in the ECM. The target engine speed is the lowest speed at which the engine can operate steadily. The optimum value stored in the ECM is determined by taking into consideration various engine conditions, such as during warming up, deceleration, and engine load (air conditioner, power steering and cooling fan operation, etc.)

Lexus Vehicle:Lexus ES,Lexus GS,Lexus GX,Lexus HS,Lexus IS,Lexus LFA,Lexus LS,Lexus LX,Lexus RX,Lexus RX,Lexus SC,Lexus GS350,Lexus GS450H,Lexus IS250,Lexus GX460,Lexus IS350,Lexus LS460,Lexus LS600H,Lexus LX570,Lexus RX350
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