What Does P2109 Mean?
The throttle position sensor is not reading the expected minimum (closed) position voltage. The PCM has detected that the throttle plate is not returning to its proper idle stop position or the sensor signal is incorrect.
Common Causes
35%
Carbon buildup on throttle plate and bore preventing full closure
30%
Faulty throttle position sensor or accelerator pedal position sensor
20%
Throttle actuator motor or return spring failure
15%
Wiring issues or poor connections to throttle body or pedal sensor
Diagnostic Steps
1
Step 1: Inspect throttle body for carbon buildup; clean throttle bore and plate with appropriate cleaner
2
Step 2: Using scan tool, monitor throttle position sensor voltages at idle and verify they match specifications (typically 0.4-0.9V closed)
3
Step 3: Perform throttle relearn/adaptation procedure per manufacturer specifications
4
Step 4: Check accelerator pedal position sensor signals for proper range and correlation
5
Step 5: Inspect throttle body connector and wiring for damage, corrosion, or loose pins
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
The throttle position sensor is not reading the expected minimum (closed) position voltage. The PCM has detected that the throttle plate is not returning to its proper idle stop position or the sensor signal is incorrect.
The most common cause of P2109 (Throttle/Pedal Position Sensor "A" Minimum Stop Performance) is: Carbon buildup on throttle plate and bore preventing full closure
Typical repair costs for P2109 range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may experience poor idle quality, stalling, or limited throttle response. Can cause unexpected power delivery or limp mode activation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2109 to identify the root cause.
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Quick Info
Category
Powertrain
System
Electronic Throttle Control
Difficulty
Type
Generic (SAE)
Recommended Tools
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