Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0505 Idle Control System Malfunction: Description
The idling speed is controlled by the ETCS (Electronic Throttle Control System). The one valve type throttle body ETCS is comprised of: 1) the throttle actuator, which operates the throttle valve; 2) the Throttle Position (TP) sensor, which detects the opening angle of the throttle valve; 3) the Accelerator Pedal Position (APP) sensor, which detects the accelerator pedal position; and 4) the ECM, which controls the ETCS. Based on the target idling speed, the ECM controls the throttle actuator to provide the proper throttle valve opening angle.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0505 | Idling speed continues to vary greatly from target idling speed (2 trip detection logic) |
|
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.