P2135 - Throttle/Pedal Position Sensor/Switch A / B Voltage Correlation

With so many working parts in the car, it’s highly probable that something will go wrong at some point. When the Check Engine Light comes on and the P2135 code is set, you don’t have to feel overwhelmed. It’s just a matter of figuring out what has gone wrong, so you can fix it.

In this guide, I explain the P2135 trouble code. I show you what it means, how it is caused, the symptoms that come from it, and the possible repairs.

Code P2135 Definition

P2135 – Throttle/Pedal Position Sensor/Switch A / B Voltage Correlation

What Does the P2135 Code Mean?

The P2135 code indicates that the voltage reading between the accelerator pedal position sensor and the throttle body position sensor doesn’t match.

This isn’t an issue on older models because the throttle body was connected directly to the accelerator with the help of a cable and a mechanical link. As the accelerator was pushed, the throttle body would open. It doesn’t get much simpler than that.

However, modern vehicles are more powerful and have stricter emissions controls. This setup requires the Engine Control Module, which monitors how the throttle operates. For this reason, a wire system was installed in the vehicle. The accelerator now contains a sensor that determines how hard you push down on the pedal. This information is sent to the throttle body to open up to the same degree.

However, P1235 sets to show that these two sensors aren’t operating at the same level. In response, the vehicle might go into a fail-safe situation, limiting how much throttle is used until the repair is made.

P2135 Trouble Code Symptoms

While it’s possible to only see the Check Engine Light with this condition, you are more than likely going to notice performance issues. These symptoms vary in intensity and frequency, depending on the cause.

Here are the top symptoms occurring with the P2135 trouble code.

Causes of the P2135 Code

Because the P2135 DTC relates to both the throttle body and accelerator pedal sensors, there could be a problem with either one. However, there are other possibilities, which is why it’s important to perform a complete diagnostic check to figure out what’s going on.

Bad throttle position sensor
Faulty throttle body actuator
Failing accelerator pedal position sensor
Damaged wiring
Faulty electrical connections

How Serious is the P2135 Code?

Severe – When the P2135 trouble code sets, you want to take action immediately. In many vehicles, the car will go into a fail-safe or limp mode, making it difficult to operate the vehicle at normal speeds. If you are on the highway, it could lead to an accident.

There’s also the possibility of the car stalling unexpectedly. Either way, an immediate repair is the only way to ensure complete safety.

What Repairs Can Fix the P2135 Code?

After you follow through on the diagnosis steps we list below, you will have a better idea of what needs to be repaired. Here are a few possible repairs that might help get your car back on the road.

Throttle position sensor replacement
Throttle body actuator replacement
Accelerator pedal position sensor replacement
Repair damaged wiring
Throttle body calibration
Repair electrical connections

Common P2135 Diagnosis Mistakes

Many people will go ahead and replace the throttle body when facing the P2135 trouble code. While this might seem logical in many cases, it’s still important to do a complete diagnosis first.

Otherwise, you might spend money to replace the throttle body when you don’t need to. Instead, you want to make sure that everything is completely checked before deciding what’s wrong. There could simply be a loose connection of bad wire.

How to Diagnose the P2135 Trouble Code

If you are trying to figure out the cause of the P2135 code, it’s important to follow the same steps for diagnosis that the professional mechanics would. While every technician handles it differently, here are a few steps you might prefer to follow.

Check all engine codes.
Clear the codes and drive the vehicle to see what new DTCs are set.
Use freeze frame data to determine what’s going on.
Look at manufacturer Technical Service Bulletins (TSBs) to see if there’s anything listed by the automaker related to the problem.
Inspect the wiring for any worn connectors. Check the throttle body and accelerator pedal wiring.
Do a calibration of the throttle body to see if the error code is going away.
If all of the wiring and connectors look good, you must use the vehicle service manual to finish inspecting the components. This manual will show you the proper parameters and procedures for the accelerator pedal position sensor and throttle body position sensor.

Estimated P2135 Repair Cost

Once you’ve been through the appropriate steps, you have an idea of what you need to get back on the road. We outline the most common repairs and the costs based on parts and labor.

Throttle position sensor replacement – $100-$350
Throttle body actuator replacement – $500-$750
Accelerator pedal position sensor replacement – $150-$350
Repair damaged wiring – $50-$500
Repair electrical connections – $50-$1,000

Mechanics Tips about the P2135 Code

Don’t ever unplug the throttle body unless absolutely necessary. If you do, the vehicle will have to go through a relearning process.

There are times when you can do this without the use of a scan tool. However, the majority of times, a scan tool will be needed for the relearn process.

Categories: OBD Codes