Dtc P0505 Idle Control System Malfunction

Engine. Lexus Gs430, Gs300. Uzs190 Grs190
3Uz-Fe Engine Control System. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

MONITOR DESCRIPTION

INSPECTION PROCEDURE

CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0505)

CHECK CONNECTION OF PCV HOSE

CHECK AIR INDUCTION SYSTEM

CHECK THROTTLE VALVE

DTC P0505 Idle Control System Malfunction


DESCRIPTION

The idle speed is controlled by the Electronic Throttle Control System (ETCS). The ETCS is comprised of: 1) one valve type throttle body; 2) the throttle actuator, which operates the throttle valve; 3) the throttle position sensor, which detects the opening angle of the throttle valve; 4) the accelerator pedal position sensor, which detects the accelerator pedal position; and 5) the ECM, which controls the ETCS. Based on the target idle speed, the ECM controls the throttle actuator to provide the proper throttle valve opening angle.

DTC No.
DTC Detection Condition
Trouble Area
P0505
Idle speed continues to vary greatly from target speed (2 trip detection logic)
  1. ETCS
  2. Air induction system
  3. PCV hose connection
  4. ECM

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 10 km/h (6 mph) or more, the actual idle RPM varies from the target RPM by -200 to -100 rpm or 100 to 200 rpm 5 times or more during a drive cycle.
Example:
If the actual idle RPM varies from the target idle RPM by more than 200 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.

Lexus Gs430, Gs300. Uzs190 Grs190.3Uz-Fe Engine Control System.Sfi System. Dtc P0505 Idle Control System Malfunction


INSPECTION PROCEDURE

HINT:
  1. The detection of DTC P0505 may also be caused by: 1) the floor carpet overlapping onto the accelerator pedal, causing the accelerator pedal to be slightly depressed (throttle position to be slightly open); or 2) the accelerator pedal not being fully released.
  2. Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was LEAN or RICH, and other data from the time the malfunction occurred.
1.CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0505)

Result:

Display (DTC output)
Proceed to
P0505
A
P0505 and other DTCs
B


B
GO TO RELEVANT DTC CHART
A


2.CHECK CONNECTION OF PCV HOSE


NG
REPAIR OR REPLACE PCV HOSE
OK


3.CHECK AIR INDUCTION SYSTEM


NG
REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK


4.CHECK THROTTLE VALVE

  1. Check the throttle valve condition.



NG
REPLACE THROTTLE BODY
OK

REPLACE ECM