P0511

DTC P0511 IDLE AIR CONTROL CIRCUIT

CIRCUIT DESCRIPTION

DTC Detecting Condition:

The rotary solenoid type idle speed control (ISC) valve is located under the throttle body and intake air bypassing the throttle valve flows to the idle speed control (ISC) 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 idle speed control (ISC) valve only to perform idle-up and provide feedback for the target idling speed.

MONITOR DESCRIPTION

Monitor Description:

Monitor Strategy:

Typical Enabling Condition:

Typical Malfunction Thresholds:

Component Operating Range:

The idle speed is determined depending on the volume of air that passes through the ISC valve. When the volume is large, the idle speed is higher. When the volume is small, the idle speed is lower. The ISC valve controls the volume of air that bypasses the throttle valve. The engine control module (ECM) sends duty signals to the ISC valve and drives the ISC valve to determine the volume of air 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 speed control (ISC) remains at the maximum or remains at the minimum, the ECM determines to detect malfunction in the ISC system.

If the rate of duty signal input to the ISC valve is stuck to 0 or 100%, the ECM interprets it as an open/short circuit in the ISC valve and sets a DTC.

Example:
If then RPM difference between the target RPM and actual RPM exceeds 200 rpm (*1) with the vehicle stopped in the idle and this occurs 5 times.
*1: The threshold is varied by an engine load.

Wiring Diagram:

INSPECTION PROCEDURE

HINT: 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 - 4:

Step 5 - 8:

Step 8 - 9:

Hand-held tester

Step 1 - 3:

Step 4 - 7:

Step (7 Continued - 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.