GMC Sierra 1500 Accelerator Pedal Sensor: A Comprehensive 2007-2018 Guide
If your truck is showing a 'Reduced Engine Power' message or hesitating when you accelerate, your accelerator pedal sensor is a likely cause.
- The 'Reduced Engine Power' message combined with poor acceleration almost always points to a failing accelerator pedal sensor.
- Diagnostic Trouble Codes P2135 and P2138 are the most common indicators for this specific failure.
- This is a very easy DIY repair that takes less than 30 minutes and requires only basic hand tools.
- Before replacing the part, check the electrical connector for corrosion or damage, as a bad connection can cause the same symptoms.
Is Your Truck in 'Limp Mode'?
One of the most common and frustrating issues Sierra owners face is the 'Reduced Engine Power' message appearing on the dashboard. This is a safety feature called 'limp mode,' designed to protect the engine when the truck's computer detects a serious problem. It severely limits your speed and acceleration, making it difficult and unsafe to drive normally. Often, this mode is triggered by a fault in the accelerator pedal sensor, which the computer sees as a critical failure.
Common Failure Symptoms
A failing accelerator pedal sensor will give you clear signs. Besides the 'Reduced Engine Power' message, you might experience:
- Poor or Delayed Acceleration: The truck may feel sluggish or hesitate for a few seconds after you press the gas pedal.
- No Throttle Response: In some cases, the truck may not accelerate at all, or only be able to move at a very slow speed.
- Check Engine Light: A fault in the pedal sensor will almost always trigger the check engine light. Common trouble codes associated with this are P2135 and P2138, which point to a voltage correlation problem between the sensor's internal circuits.
- Rough or High Idle: The engine might idle unevenly or at a higher RPM than usual because the computer is getting incorrect signals from the pedal.
Known Issues and Recalls
While there was a recall for 2014 Sierra models (NHTSA #14310) related to floor mats interfering with the pedal, it was not for the sensor itself. However, General Motors has issued multiple Technical Service Bulletins (TSBs) and Special Coverage programs for other vehicles with the same engine platforms and identical symptoms (like DTC P2135). This indicates that a failing pedal sensor is a well-known issue across many GM vehicles of this era.
Choosing the Right Aftermarket Part: OEM vs. Aftermarket
When replacing the accelerator pedal sensor, you have a choice between Original Equipment (OEM) from a dealer like ACDelco and aftermarket parts from brands like Standard Ignition.
- OEM (ACDelco/GM Genuine): These are the exact same parts your truck was built with. They guarantee perfect fit and function, but they typically come at a higher price.
- Aftermarket (Standard Ignition): A reputable aftermarket brand like Standard Ignition designs its parts to meet or exceed original specifications. They are a cost-effective alternative and are often readily available. Standard Motor Products (the parent company) notes their sensors are 100% tested and use durable materials. For a straightforward part like this, a quality aftermarket sensor is a reliable choice for most owners.
Typical Replacement Costs
| Part Type | Estimated Cost |
|---|---|
| New OEM | $120 - $165 |
| New Aftermarket (Standard Ignition) | $93.84 |
| Shop Labor | $85 - $125 |
Cost estimates are based on national averages and may vary by location and supplier.
Frequently Asked Questions
Is this a difficult part to replace myself?
No, this is one of the easiest repairs you can do. 🎬 See this walkthrough for replacing the pedal on 2007-2013 trucks. The accelerator pedal assembly is typically held to the firewall by two or three bolts and has a single electrical connector. Basic hand tools are all that's required, and the job can be done in under 30 minutes.
🎬 Watch: Step-by-step accelerator pedal replacement for 2014-2018 Sierra models.Can I drive my truck with a bad accelerator pedal sensor?
You can, but it is not recommended. The truck will likely be in 'Reduced Engine Power' mode, with very limited acceleration. This can be dangerous in traffic when you need to merge or keep up with the flow of traffic. It's best to get it repaired as soon as possible.
How do I know it's the sensor and not something else?
The best way to confirm is to have the Check Engine Light codes read by an OBD-II scanner. Codes like P2135 or P2138 are a strong indication that the accelerator pedal sensor is the problem. These symptoms are very specific to this part's failure.
Does the new sensor need to be programmed?
No. For this specific part on the 2007-2018 Sierra, the replacement is plug-and-play. You do not need to perform any special programming or relearn procedures after installation. Some sources mention a relearn procedure for the throttle body if it is replaced, but not for just the pedal sensor.
Helpful Videos
Technical Specifications
OEM Part Numbers: 25832864 15847349 15101848 20972082 23362231
The accelerator pedal sensor is sold as a complete pedal assembly. It is a floor-mounted unit with a 6-pin electrical connector. The part is made of high-impact plastic and contains dual return springs for safety and pedal feel.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- GMC Sierra 1500: