What Does P0510 Mean?
The closed throttle position switch or sensor is not reporting a valid signal when the PCM expects the throttle to be at the idle (closed) position. This switch/sensor input tells the PCM when the driver's foot is off the accelerator so it can manage idle speed control and deceleration fuel cut-off strategies. The driver may experience high idle, inability to return to normal idle, or harsh deceleration due to incorrect fuel cut-off timing.
Common Causes
35%
Misadjusted or failed closed throttle position switch
25%
Throttle body carbon buildup preventing the plate from fully closing to the switch contact point
20%
Wiring fault in the closed throttle position switch circuit
12%
Binding throttle cable preventing full return to idle position
8%
Faulty PCM input processing for the closed throttle signal
Diagnostic Steps
1
Monitor the TPS voltage at closed throttle — it should read the manufacturer's specified closed voltage (typically 0.4-0.9V). Compare to the closed throttle switch PID if available.
2
With the ignition on and engine off, manually open and close the throttle while watching the closed throttle switch PID — it should cleanly toggle between open and closed states.
3
Clean the throttle body and verify the throttle plate returns fully to its mechanical stop — carbon deposits can prevent full closure.
4
Check the closed throttle switch or TPS connector for corrosion, bent pins, or loose terminals. Verify proper reference voltage and ground at the sensor.
5
If the throttle position switch is adjustable, follow the manufacturer's procedure to set it correctly using a feeler gauge or multimeter to verify the switching point.
Estimated Repair Cost
$30 - $250
Parts + labor, varies by vehicle and location
The closed throttle position switch or sensor is not reporting a valid signal when the PCM expects the throttle to be at the idle (closed) position. This switch/sensor input tells the PCM when the driver's foot is off the accelerator so it can manage idle speed control and deceleration fuel cut-off ...
The most common cause of P0510 (Idle Control System RPM Higher Than Expected) is: Misadjusted or failed closed throttle position switch
Typical repair costs for P0510 range from $30 to $250, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle is drivable but may exhibit high idle that causes creeping in gear. Fuel efficiency may decrease and deceleration behavior may be abnormal. Repair at your earliest convenience to restore proper idle control and fuel economy.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0510 to identify the root cause.
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Quick Info
Category
Powertrain
System
Idle Control System / Throttle Control
Difficulty
Type
Generic (SAE)
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