P0122 code: Throttle Position Sensor/switch "A" Circuit Low

What does P0122 code mean?

The P0122 code is a general OBD-II diagnostic trouble code (DTC) that indicates a fault within the TPS (Throttle/pedal Position Sensor/switch) circuit. It’s usually related to low voltage output from the TPS to the car’s electronic control unit (ECU).

This DTC indicates that the car has detected an input malfunction in the throttle position sensor circuit. A throttle position sensor measures how far open or closed an accelerator pedal is and reports it back to the ECU, which then adjusts ignition timing and other engine functions. If a problem is detected with this sensor, it could result in reduced engine performance, decreased fuel efficiency and overall poor drivability.

On most vehicles sold in North America, you can diagnose and clear a P0122 code yourself with only basic hand tools (namely, a multimeter), though some specialized knowledge of automotive systems will help you understand what’s going on inside your car as well as make sure your fixes are permanent. You’ll need to be able to check voltage output through both wires of your TPS using your multimeter, as well as run diagnostics on other potential causes of this issue like bad wiring or connectors.

What Causes P0122?

There are many things that can cause the P0122 code. Here are some of the most common:

Faulty throttle position sensor
Broken wiring or connectors to the TPS
Faulty PCM (rare)
Low voltage in the engine control unit
Low oil level
Faulty oil pressure sensor
Faulty oil pump

What Are the Symptoms of a P0122 Code?

When a P0122 code is flagged, your vehicle’s Check Engine light will be illuminated until the code is fixed. Often, this is the only indication that there’s something wrong with your vehicle. That said, you may notice a decrease in performance and fuel economy.

Most of the time, a P0122 code means that your vehicle’s throttle position sensor is malfunctioning or has failed outright. In some cases, it could also be that your throttle body itself has failed. In less common instances, it could be an issue with the throttle position sensor connector or wiring associated with it (such as bad terminals or a poor connection).

How to Diagnose a P0122 Code?

With the P0122 code, it’s important to check for any pending codes before starting a test drive. This will help to ensure that there are no other pending codes that need to be cleared before starting the engine—this will prevent any additional faults from being created. In addition, if you are going to be driving the car after this procedure, it’s important to make sure there is nothing stored in memory before doing so. If something is stored in memory, like a freeze frame data, you may have issues with starting your car or repeat trips of high-performance driving.

Common Misdiagnoses

Perhaps the most common misdiagnosis that can be made in relation to a P0122 code is to think that it’s actually a P0122 code. This is an understandable mistake, since both codes relate to the same thing: a voltage drop from the TPS sensor. To avoid this error, make sure you’re looking at the right code for your car!

How to Fix it?

The best way to fix a P0122 code is to replace the TPS. You should also inspect the TPS connector and wiring for any damage or corrosion. If you’re going to replace the TPS yourself, park your car on a level surface, engage the parking brake, and let your engine cool down before attempting any repairs.