P2135 Code: Impact on Performance and How to Fix It

P2135 Code: Impact on Performance and How to Fix It

Have you recently seen the dreaded check engine light illuminate on your dashboard, only to discover the mysterious P2135 code when scanning your vehicle? Don’t worry – you’re not alone. This common diagnostic trouble code (DTC) affects a wide range of vehicles and can be a source of frustration for many car owners. In this comprehensive guide, we’ll break down what the P2135 code means, how it impacts your vehicle, and most importantly, how to diagnose and fix the issue.

What is the P2135 Code?

The P2135 code stands for “Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation.” In simpler terms, this means there’s a discrepancy between the voltage signals from your throttle position sensor (TPS) and accelerator pedal position (APP) sensor. These sensors are crucial components of your vehicle’s electronic throttle control system, which manages the airflow into your engine based on how much you’re pressing the gas pedal.

Top 20 Vehicles Commonly Affected by P2135

While this code can appear in various makes and models, here are some vehicles that frequently experience the P2135 code:

  • Chevrolet Silverado (2008-2011)
  • GMC Sierra (2008-2011)
  • Chevrolet Tahoe (2008-2011)
  • GMC Yukon (2008-2011)
  • Chevrolet Suburban (2008-2011)
  • Cadillac Escalade (2008-2011)
  • Chevrolet Avalanche (2008-2011)
  • Chevrolet Express (2008-2011)
  • GMC Savana (2008-2011)
  • Chevrolet Colorado (2009-2011)
  • GMC Canyon (2009-2011)
  • Chevrolet TrailBlazer (2008-2009)
  • GMC Envoy (2008-2009)
  • Hummer h3 (2008-2009)
  • Hummer h4 (2008-2010)
  • Chevrolet Impala (2006-2011)
  • Pontiac G6 (2006-2010)
  • Saturn Aura (2007-2009)
  • Buick Lucerne (2006-2011)
  • Chevrolet Malibu (2008-2012)

Impact on Vehicle Performance and Emissions

When your vehicle triggers the P2135 code, it’s not just a minor inconvenience. This issue can significantly affect both performance and emissions:

Performance Impact:

  • Reduced engine power
  • Poor acceleration
  • Erratic idle
  • Stalling
  • Entering “limp mode” (reduced power mode for safety)

Emissions Impact:

  • Increased fuel consumption
  • Higher emissions due to improper air-fuel mixture
  • Potential failure of emissions tests

Diagnosing and Fixing P2135

Key Symptoms:

  • Check Engine Light illuminated
  • Reduced engine power
  • Difficulty accelerating
  • Stalling or rough idle
  • Higher than normal RPMs

Diagnostic Steps:

  1. Use an OBD-II scanner to confirm the P2135 code
  2. Visually inspect the throttle body and pedal assembly for damage or debris
  3. Check wiring and connectors for signs of wear, corrosion, or loose connections
  4. Test the throttle position sensor and accelerator pedal position sensor using a multimeter
  5. Inspect the throttle body for carbon buildup or sticking

Potential Solutions:

  • Clean the throttle body if carbon buildup is present
  • Replace faulty throttle position sensor or accelerator pedal position sensor
  • Repair or replace damaged wiring or connectors
  • In some cases, replacing the entire throttle body assembly may be necessary
  • Update the Engine Control Module (ECM) software if available

Frequently Asked Questions

Q: Is it safe to drive with the P2135 code?

A: While you may be able to drive short distances, it’s not recommended. The code can cause unpredictable acceleration and potential stalling, which can be dangerous in traffic.

Q: How much does it cost to fix P2135?

A: Repair costs can vary widely depending on the root cause and your vehicle model. Simple fixes like cleaning the throttle body may cost around $100, while replacing sensors or the entire throttle body can range from $200 to $1000 or more.

Q: How can I prevent P2135 from occurring?

A: Regular maintenance is key. Keep your throttle body clean, ensure your battery is in good condition, and address any check engine lights promptly. Also, avoid using low-quality fuel that can lead to carbon buildup.


The P2135 code, while common, should not be ignored. Addressing this issue promptly is crucial for maintaining your vehicle’s performance, fuel efficiency, and compliance with emission standards. If you’re not comfortable diagnosing or repairing the issue yourself, don’t hesitate to consult a professional mechanic. Remember, a well-maintained vehicle not only performs better but also saves you money in the long run by preventing more serious issues down the road.

By understanding the P2135 code and its implications, you’re taking an important step in becoming a more informed and responsible vehicle owner. Keep this guide handy, and you’ll be well-equipped to handle this common automotive challenge.

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