Faulty or misadjusted closed throttle switch or idle switch; Damaged, corroded or loose wiring or connector at the switch or throttle body; Dirty or worn throttle body or throttle position sensor giving a signal that disagrees with the switch; Throttle linkage or return spring sticking or incorrectly set so the throttle does not fully close; Air leak or idle control fault causing the control unit to see an unexpected idle condition; Internal fault in the engine control unit.

P0510

Closed Throttle Position Switch.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
5: AreaVehicle speed, idle control and auxiliary inputs
10: FaultThe specific fault in that area

What it means

P0510 is the generic SAE J2012 code for a fault in the closed throttle position switch circuit. The engine control unit expects the idle or closed throttle switch signal to agree with other inputs such as throttle position sensor voltage, engine speed and load, and it has seen a signal that is stuck, missing or contradictory. It is mostly seen on older or specific designs that use a separate idle switch, while many modern drive-by-wire cars cover this function within the throttle position sensors.

Symptoms

Engine management warning light on
Unstable, too high or too low idle speed
Engine stalling when you lift off or come to a stop
Poor or hesitant throttle response
Idle speed not dropping after lifting off the accelerator
Slightly heavier fuel use

Possible causes

Faulty or misadjusted closed throttle switch or idle switchlikely
Damaged, corroded or loose wiring or connector at the switch or throttle bodylikely
Dirty or worn throttle body or throttle position sensor giving a signal that disagrees with the switchpossible
Throttle linkage or return spring sticking or incorrectly set so the throttle does not fully closepossible
Air leak or idle control fault causing the control unit to see an unexpected idle conditionpossible
Internal fault in the engine control unitrare

How to diagnose

Read the stored codes and freeze frame data, noting engine speed, load, throttle position and coolant temperature when the code set, and check for other related codes
Visually inspect the throttle body, linkage, return spring and cable for sticking, damage or incorrect adjustment
Inspect the wiring and connectors to the switch and throttle body for chafing, corrosion, water ingress and loose pins
Check the live data for the closed throttle switch status and throttle position, and confirm the switch changes state smoothly as the pedal is pressed and released
Measure the switch circuit supply, signal and earth against the manufacturer's data, and test for continuity and shorts in the wiring
Check for vacuum leaks and inspect the idle control system, as the correct procedure depends on the model and engine
Clean the throttle body if it is dirty, then perform any throttle adaptation or relearn the manufacturer specifies
Clear the code and road test, then recheck live data to confirm the fault does not return

How to fix

Replace or correctly adjust the closed throttle switch or throttle position sensor, following the manufacturer's procedure for your model
Repair or replace damaged wiring and clean or renew corroded connectors
Clean the throttle body and free or replace sticking linkage or a weak return spring
Repair any vacuum leaks and idle control faults found
Carry out the throttle adaptation or idle relearn after any repair where the manufacturer requires it
Replace or repair the engine control unit only after all wiring, sensor and mechanical causes are ruled out

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but a poor or unstable idle and possible stalling can be a safety concern in traffic. Get it checked soon rather than leaving it.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.