P0505

DTC P0505 Idle Air Control System

CIRCUIT DESCRIPTION

DTC Detecting Condition:

The rotary solenoid type Idle Air Control (IAC) valve is located in front of the intake air chamber, and the intake air bypassing the throttle valve flows to the IAC valve through a passage. In this way the intake air volume bypassing the throttle valve is regulated, controlling the engine speed.

The ECM operates only the IAC valve to perform the idle-up operation and to provide feedback for the target idling speed.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

Component Operating Range:

The idling speed is determined depending on the volume of air that passes through the intake air control (IAC) valve. When the volume is large, the idling speed becomes higher. When the volume is small, the idling 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 motor to regulate the air volume that bypasses the throttle valve.

Although the ECM regulates the engine idling RPM with feedback control in several vehicle stopped, actual idling RPM does not reach the targeted RPM and a learned valve opening duty ratio of the IAC remains at the maximum or remains at the minimum, the ECM determines to detect a malfunction in the IAC system.

Example:
If the difference between the targeted and actual engine idling RPMs exceeds 200 rpm (*1) with the vehicle stopped while idling, and this occurs 5 times, or if the learned valve angle of the IAC remains at the maximum or minimum angles for 5 seconds, DTC P0505 is set.

P0511 is set as an open/short circuit in the IAC if the duty signal ratio transmitted to the IAC valve remains at 0 % or 100 %.

*1: Threshold RPM varies in accordance with an engine load.

Wiring Diagram:

INSPECTION PROCEDURE

HINT:
- 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 (TP to be slightly open); or 2) the accelerator pedal not being fully released.
- In case of using the hand-held tester or OBD II scan tool, start the inspection from step 1 and in case of not using the hand-held tester, start from step 2.
- Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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.

Step 1 - 2:

Step 3 - 4:

Step 5 - 7:

Step 8 - 9:

Hand-held tester:

Step 1 - 4:

Step 5 - 6:

Step 7:

OBD II scan tool (excluding the hand-held tester):

CHECK FOR INTERMITTENT PROBLEMS

HINT:

Hand-held tester only:
Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect with the hand-held tester when the ECM is in check mode. In check mode, the ECM uses 1trip detection logic, which is more sensitive to malfunctions than normal mode (default) that uses 2trip detection logic.

a. Clear DTCs.
b. Switch the ECM from normal mode to check mode using a hand-held tester.
c. Perform a simulation test.
d. Check and wiggle the harness(es), the connector(s) and terminal(s).