What is the P0505 fault number? What is the Idle Controller System (IAC), fault description? How do you fix the P0505 fault code What are the causes and symptoms of the P0505 error code?
What is the P0505 fault code? What does it mean
Your vehicle’s primary computer (called the powertrain controller module (PCM)), detects an idle air control system problem and alerts you. The PCM logs the correct diagnostic trouble code. P0505 is one of the possible codes in the scanner.
Fault code P0505 is a sign “Idle Control System Malfunction” . This code may also indicate other issues such as unsteady idle speed or stalling.
Older vehicles depend on an idle control valve (IAC), which is mounted near the throttle body. It regulates the vehicle’s idle speed. To maintain idle speed, the IAC valve measures bypass air around throttle plate. The throttle plate closes when the vehicle is idle and restricts airflow to the engine. But, the engine still requires air to run. The idle control system will open the bypass air passage according to the instructions in the PCM. This alternative route allows air flow to reach the engine by bypassing the throttle plate.
The idle control system adjusts the clearance of the bypass air passage to regulate the amount of air that is supplied to the engine when it is idle. It has a cap or plunger that allows it to do this. It can either increase the idle speed by absorbing more air, or decrease the flow to reduce it.
The PCM tracks the current load on the idling motor. It adjusts idle control to make sure the engine has the air it requires.
Like all car parts, the idle control system can be damaged over time. It can fail or begin to fail and affect the engine’s idle speed, which will cause the PCM to issue a P0505 error code.
What is the P0505 Fault Code and Why Does It Happen?
- – Defective idle control (IAC), valve
- – IAC valve stuck due to excessive carbon deposits
- IAC air ducts blocked by dirt, debris, or carbon
- Vacuum leaks in intake system after throttle body
- – IAC circuit problems, such as loose connections or damaged wires
- – Non-calibration idle speeds (relearn needed)
- – PCM-related issues like software that needs to be updated
What are the symptoms of P0505 Malfunction Code?
- – Illumination for the check engine light
- – If the gas is not pressed, the engine will stop and misfire.
- – Too fast engine speed at idle
- Too low engine speed at idle
- – Irregular speed fluctuations
IAC-related faults can only be detected when the engine is running and the throttle is not closed.
How to Fix the P0505 Fault Code
- – Repair damaged wiring and loose connections to IAC circuit
- – Replacing IAC valve
- – Clean the throttle body and passages
- Cleaning carbon deposits from IAC air valve and IAC duct
- Repair vacuum leaks in intake manifolds or gaskets
How serious is the P0505 Fault code?
Fault code 0505 means that the IAC vale is not functioning properly. This could cause the engine’s idle to be very low or high and can even cause it to stall.
