What Does P2122 Mean?
The PCM has detected that the voltage signal from accelerator pedal position sensor 'D' is below the acceptable minimum threshold. This typically indicates a short to ground, sensor failure, or wiring issue causing abnormally low voltage.
Safety Warning
Engine will enter fail-safe mode with no throttle response or fixed idle speed only. Vehicle cannot be driven safely; requires immediate repair and should be towed.
Common Causes
35%
Short to ground in accelerator pedal position sensor 'D' signal circuit wiring
35%
Failed accelerator pedal position sensor with internal short
20%
Damaged or corroded connector causing short circuit or poor contact
10%
PCM internal circuit failure causing sensor input to read low
Diagnostic Steps
1
Step 1: Disconnect accelerator pedal position sensor connector and measure sensor 'D' signal voltage at PCM side; should see 5V reference with sensor disconnected
2
Step 2: Check sensor signal wire for shorts to ground using a multimeter in resistance mode (key off, harness disconnected both ends)
3
Step 3: With sensor connected, backprobe sensor 'D' signal wire and verify voltage output; should be approximately 0.5-1.0V at rest
4
Step 4: Inspect connector and wiring for damage, moisture, or corrosion that could cause short circuit
5
Step 5: If wiring is intact, replace accelerator pedal position sensor assembly
Estimated Repair Cost
$120 - $650
Parts + labor, varies by vehicle and location
The PCM has detected that the voltage signal from accelerator pedal position sensor 'D' is below the acceptable minimum threshold. This typically indicates a short to ground, sensor failure, or wiring issue causing abnormally low voltage.
The most common cause of P2122 (Throttle/Pedal Position Sensor/Switch "D" Circuit Low) is: Short to ground in accelerator pedal position sensor 'D' signal circuit wiring
Typical repair costs for P2122 range from $120 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Engine will enter fail-safe mode with no throttle response or fixed idle speed only. Vehicle cannot be driven safely; requires immediate repair and should be towed.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2122 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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