AutoCodes – Generic – P2120

P2120 Code - Throttle/Pedal Position Sensor/Switch 'D' Circuit

Quick Answer

The Accelerator Pedal Position (APP) sensor is an input to the Powertrain Control Module (PCM) and used to determine the amount of torque requested by the operator. Common causes include Faulty Accelerator Pedal Position (APP) Sensor, Accelerator Pedal Position (APP) Sensor harness is open or shorted, Accelerator Pedal Position (APP) Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P2120 indicates Throttle/Pedal Position Sensor/Switch 'D' Circuit.
Common causes: Common causes include Faulty Accelerator Pedal Position (APP) Sensor, Accelerator Pedal Position (APP) Sensor harness is open or shorted, Accelerator Pedal Position (APP) Sensor circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 24,729

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P2120 Description

The Accelerator Pedal Position (APP) sensor is an input to the Powertrain Control Module (PCM) and used to determine the amount of torque requested by the operator. There are 2 pedal position signals in the sensor. Both signals, APP and APP2, have a positive slope (increasing angle, increasing voltage), but are offset and increase at different rates. The 2 pedal position signals make sure the PCM receives a correct input even if 1 signal has a concern. The PCM determines if a signal is incorrect by calculating where it should be, inferred from the other signals. If a concern is present with one of the circuits the other input is used. There are 2 reference voltage circuits, 2 signal return circuits, and 2 signal circuits (a total of 6 circuits and pins) between the PCM and the APP sensor assembly. The pedal position signal is converted to pedal travel degrees (rotary angle) by the PCM. The software converts these degrees to counts, which is the input to the torque based strategy.

OBDII Code P2120 - Throttle/Pedal Position Sensor/Switch 'D' Circuit - AutoCodes.com — P2120 Code - Throttle/Pedal Position Sensor/Switch 'D' Circuit

What does this mean?

What are the Possible Causes of the DTC P2120?

Faulty Accelerator Pedal Position (APP) Sensor
Accelerator Pedal Position (APP) Sensor harness is open or shorted
Accelerator Pedal Position (APP) Sensor circuit poor electrical connection
Faulty Powertrain Control Module (PCM)

How to Fix the DTC P2120?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2120 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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Information for Specific Makes

P2120 Buick — Accelerator Pedal Position Sensor 1 Circuit
P2120 Cadillac — Accelerator Pedal Position Sensor 1 Circuit
P2120 Chevrolet — Accelerator Pedal Position Sensor 1 Circuit
P2120 Chrysler — Throttle/Pedal Position Sensor/Switch 'D' Circuit
P2120 Dodge — Throttle/Pedal Position Sensor/Switch 'D' Circuit
P2120 GMC — Accelerator Pedal Position Sensor 1 Circuit
P2120 Hyundai — Throttle/Pedal Position Sensor/Switch 'D' Circuit
P2120 Jeep — Throttle/Pedal Position Sensor/Switch 'D' Circuit
P2120 Lexus — Throttle Pedal Position Sensor/Switch 'D' Circuit
P2120 Scion — Throttle Pedal Position Sensor/Switch 'D' Circuit
P2120 Toyota — Throttle Pedal Position Sensor/Switch 'D' Circuit

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.