P2120 code meaning
Throttle/Pedal Position Sensor/Switch D Circuit
Powertrain system Generic code P21xx codes Check engine light
What P2120 means
P2120 is the general circuit check for signal D, which GM, Ford and VW all use for the first accelerator pedal track. GM's 2007 tables call it APP Sensor 1 Circuit: the ECM watches sensor 1 for steady or intermittent opens and shorts within its 0.325-4.75 V window and counts failures every 12.5 ms, setting the code at 19 of 39 counts. GM PIP3783D lists P2120 among the pedal codes on 2007-2014 full-size trucks and SUVs and blames weak pin grip in the inline connectors C109 and C205. Ford's 2024 summary uses P2120 as the base code whose failure types 16 and 17 replace P2122 and P2123. Range/Performance is P2121, low and high voltage P2122/P2123, dropouts P2124. With one track lost, the ECU cuts power.
P2120 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2120
- Engine warning lamp and reduced power message
- Sluggish or capped acceleration
- Fault often intermittent and hard to reproduce
Common causes of P2120
- Most likelyPoor terminal tension or corrosion at pedal, inline or ECM connectors
- PossibleOpen or short in the sensor 1 signal, reference or ground wire
- PossibleInternal fault in the pedal sensor, such as a cracked solder joint
- Less likelyECM input fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Accelerator pedal position sensorPedal sensor wiringECM
What each part of P2120 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 1 | Area: fuel and air metering. |
| 20 | The exact fault in that area. |
What to do next
- Note P2120 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2120
What does P2120 mean?
P2120 means "Throttle/Pedal Position Sensor/Switch D Circuit". P2120 is the general circuit check for signal D, which GM, Ford and VW all use for the first accelerator pedal track. It is a generic code, so it means the same on every make.
Is it safe to drive with P2120?
Drive gently and only to a workshop. With P2120 the car can go into limp mode (reduced power) to protect itself.
Will P2120 fail an emissions test?
Yes, it can. P2120 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2120 to fix?
Difficulty: easy. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2120 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.