OBD-II Code P2122 — What It Means & How to Fix It

What Does This Error Mean?

P2122 means the Throttle/Pedal Position Sensor D circuit voltage is too low. This sensor (also called the accelerator pedal position sensor) tells the PCM how far you have pressed the gas pedal. When the signal voltage drops below the acceptable minimum, P2122 is set. The car will typically enter limp mode — acceleration feels sluggish or the pedal seems unresponsive. This code is separate from throttle body sensor codes — it specifically refers to the accelerator pedal sensor.

Affected Models

Common across all modern makes with electronic drive-by-wire throttle
Frequently seen in Ford, GM, Chrysler, and import vehicles
Common in Dodge Ram, Jeep Grand Cherokee, and Chrysler 300
Seen in Nissan, Toyota, and Honda models with electronic throttle

Common Causes

Faulty accelerator pedal position (APP) sensor — worn or failed signal circuit
Damaged wiring or connector at the pedal position sensor — short to ground or broken wire
Moisture or corrosion in the APP sensor connector under the dash
Poor ground connection at the APP sensor reducing the reference voltage
PCM input circuit fault causing it to misread the sensor voltage

How to Fix It

Do not drive at highway speeds with P2122 active. The pedal signal is unreliable, making safe acceleration control impossible.

Limp mode is protecting you — drive only at low speeds to reach a safe location.
Locate the accelerator pedal position sensor connector under the dashboard at the top of the gas pedal.

The connector is typically a 6-pin connector on a harness routed along the firewall.
Inspect the connector for moisture, corrosion, bent pins, or a loose connection. Disconnect and reconnect it firmly.

Moisture under the dash near the pedal is a surprisingly common cause of APP sensor codes.
Use a multimeter or scan tool to check the APP sensor signal voltage with the key on and pedal at rest.

Typical reference voltage is 5 volts. At rest, the signal should be around 0.5 to 1.0 volts. Below 0.3 volts indicates a fault.
Replace the accelerator pedal assembly if the sensor voltage is consistently out of range or does not change smoothly when the pedal is pressed.

Most APP sensors are integral to the pedal assembly and are replaced as a complete unit.

When to Call a Professional

Accelerator pedal position sensor replacement is $30 to $100 in parts. On most vehicles it is part of the pedal assembly — the full pedal is replaced as one unit. Labor is typically 30 to 60 minutes — total shop cost is $100 to $300. This is a safety-relevant repair — do not delay.

Frequently Asked Questions

Is P2122 different from a throttle position sensor (TPS) code?

Yes. The TPS codes (P0120 to P0124) refer to the sensor inside the throttle body on the engine. P2122 refers to the accelerator pedal position sensor located at the gas pedal under the dashboard. These are two separate sensors in a drive-by-wire system.

Can I drive with P2122 if the car seems to drive okay?

The risk is that the pedal signal is unreliable — it may work most of the time but fail at a critical moment. This could result in sudden loss of acceleration on a highway or intersection. Avoid extended or high-speed driving until this code is repaired.

Can a loose connector cause P2122?

Absolutely — this is one of the most common causes. The APP sensor connector under the dash can work loose over time. Simply unplugging and firmly reconnecting the connector has resolved P2122 on many vehicles. Always check the connector first before buying parts.