Troubleshooting
DTC P0505 IDLE AIR CONTROL SYSTEMCIRCUIT DESCRIPTION
DTC Detecting Condition:
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 idle-up and provides feedback for the target idling speed.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
Component Operating Range:
The idle speeds are determined depending on the volume of air that passes through the intake air control (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 ECM sends duty signals to the IAC valve and drives the IAC valve stepper motor to regulate 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 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 ISC remains at its maximum or minimum angle for 5 seconds, P0505 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.
Wiring Diagram:
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 the accelerator pedal, etc., DTC P505 will possibly be detected.
Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
Step 1 - 3:
Step 4 - 7:
Step 8 - 9:
Hand-held tester
Step 1:
Step 2 - 6:
Step 7 - 8:
OBD II scan tool (excluding hand-held tester)
CHECK FOR INTERMITTENT PROBLEMS
Hand-held tester only:
By putting the vehicle's ECM in the check mode, the 1 trip detection logic is possible instead of the 2 trip detection logic, and the sensitivity to detect faults is increased. This makes it easier to detect intermittent problems.
a. Clear the DTCs.
b. Set the check mode.
c. Perform a simulation test.
d. Check the connector and terminal.
e. Wiggle the harness and connector.