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Home >> Lexus >> 2006 >> GX 470 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTC P0335 - P0630 >> DTC P0505: Idle Control System Malfunction >> Monitor Description

Monitor Description

The ECM detects idle speed and idle air flow amount for Idle Speed Control (ISC). The ECM concludes that the ISC is malfunctioning if: 1) the learned value of the ISC remains at the maximum or minimum 5 times or more during a drive cycle, and 2) while driving at 6 mph (10 km/h) or more, the actual idle rpm varies from the target rpm by between 100 to 150 rpm 5 times or more during a drive cycle.

Example:

If the actual idle rpm varies from the target idle rpm by more than 100 rpm* 5 times during a drive cycle, the ECM will turn on the MIL and a DTC is set.

HINT:

*: rpm threshold varies with engine load.

Fig 1: Identifying Idle Control System Malfunction Graph
G04967984Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.