How to Diagnose and Repair the P0122 Throttle Position Sensor Code

How to Diagnose and Repair the P0122 Throttle Position Sensor Code

The P0122 code stands for “Throttle Position Sensor/Switch A Circuit Low Input“. In simpler terms, this means that your vehicle’s computer has detected an unusually low voltage signal from the throttle position sensor (TPS) circuit.

The throttle position sensor plays a vital role in your engine’s operation. It monitors the position of the throttle plate, which controls how much air enters the engine. This information helps the engine control module (ECM) determine the correct air-fuel mixture and ignition timing. When the TPS malfunctions, it can lead to various performance issues.

Top 20 Vehicles Commonly Affected by P0122

While this code can appear in many vehicles with electronic throttle control systems, here are 20 models that frequently experience this issue:

  • Chevrolet Silverado
  • Ford F-150
  • Toyota Camry
  • Honda Accord
  • Nissan Altima
  • GMC Sierra
  • Dodge Ram 1500
  • Honda Civic
  • Toyota Corolla
  • Ford Focus
  • Chevrolet Cruze
  • Hyundai Sonata
  • Kia Optima
  • Volkswagen Jetta
  • Mazda 3
  • Subaru Outback
  • Jeep Grand Cherokee
  • Ford Escape
  • Chevrolet Equinox
  • GMC Acadia

Implications on Vehicle Performance and Emissions

The P0122 code can have several negative impacts on your vehicle:

  • Reduced engine performance and power
  • Poor fuel economy
  • Increased emissions
  • Difficulty starting the engine
  • Engine misfires or stalling
  • Rough idling
  • Delayed or harsh transmission shifts

These issues not only affect your driving experience but can also lead to failed emissions tests and potential damage to other engine components if left unaddressed.

Diagnosing and Fixing P0122

Symptoms to Look Out For:

  • Illuminated check engine light
  • Engine misfires or runs rough
  • Hard starting or no-start condition
  • Poor fuel economy
  • Reduced engine power
  • Hesitation during acceleration

Diagnostic Steps:

  1. Use an OBD-II scanner to confirm the P0122 code and check for any additional codes.
  2. Visually inspect the throttle position sensor and its wiring for damage or loose connections.
  3. Check the sensor’s voltage output using a multimeter.
  4. Inspect the throttle body for carbon buildup or sticking.
  5. Check the ECM for any signs of damage or corrosion.

Potential Fixes:

  • Clean or replace the throttle position sensor.
  • Repair or replace damaged wiring or connectors.
  • Replace a faulty throttle position sensor.
  • Clean the throttle body if carbon buildup is present.
  • In rare cases, replace the ECM if it’s determined to be faulty.

Frequently Asked Questions

Is it Safe to Drive with the P0122 Code?

While your vehicle may still run, it’s not recommended to drive for extended periods with this code. The engine may run poorly, stall unexpectedly, or suffer damage over time.

How Much Does it Cost to Fix a P0122 Code?

Costs can vary widely depending on the root cause and your vehicle model. Replacing a throttle position sensor typically costs between $100-$400, while more complex issues involving wiring or the ECM can cost significantly more.

How Can I Prevent the P0122 Code from Occurring?

Regular maintenance is key. Keep up with your vehicle’s recommended service schedule and address any engine performance issues promptly. Also, avoid exposing engine components to excessive heat or moisture.


The P0122 code is more than just an annoying check engine light – it’s a sign that your vehicle’s engine management system is struggling to operate efficiently. Addressing this issue promptly can prevent more serious engine problems, improve your fuel economy, and ensure your vehicle passes emissions tests.

Remember, while some car enthusiasts may feel comfortable tackling this issue themselves, don’t hesitate to consult a professional mechanic if you’re unsure. Your vehicle’s performance and longevity are worth the investment in proper diagnosis and repair.

By staying proactive and addressing the P0122 code quickly, you’ll keep your vehicle running smoothly and efficiently for years to come. Happy driving!

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