P2135 Code – Meaning, Causes, Symptoms (& How To Fix)

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.

We will be explaining the P2135 code in this guide. This guide will explain what the P2135 trouble code is, its causes, symptoms, and possible fixes. 

Definition of the code P2135

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

What does the P2135 code mean?

The ECM monitors voltage movement between the accelerator pedal position sensor and the throttle body positioning sensor. When these voltage readings don’t match, the ECM will set the P2135 code to alert you of the problem. 

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. When the accelerator was pressed, the throttle would open. It didn’t get much simpler than that.

Modern cars are much more powerful, and they have tighter emissions control. The Engine Control Module monitors the operation of the throttle. The vehicle was equipped with a wire system. Now, the accelerator has a sensor which determines how hard you press down on your pedal. This data is transmitted to the throttle body so that it opens to the same degree.

However, P1235 sets to show that these two sensors aren’t operating at the same level. The vehicle may then go into failsafe mode, restricting throttle use until repairs are made. 

RELATED: 8 Symptoms of a Bad Throttle Body (& Replacement Cost)

Trouble Code P2135: 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. It is possible for symptoms to vary in severity and frequency depending on their cause.

These are some of the most common symptoms that occur with P2135 code trouble code. 

The P2135 Code: Causes

The P2135 DTC refers to the accelerator pedal sensor and the throttle body sensors. This could indicate that one of them is not working properly. However, there are other possibilities, which is why it’s important to perform a complete diagnostic check to figure out what’s going on.

Is the P2135 Code a Serious Issue?

Extreme – When the P2135 trouble code sets, you want to take action immediately. Many vehicles will put the vehicle in a limp or fail-safe mode. This makes it hard to drive the vehicle at normal speed. It could cause an accident if you're on the highway.

There’s also the possibility of the car stalling unexpectedly. In either case, immediate repairs are the best way to guarantee safety.

READ MORE: Throttle Body Service – What Is It and Is it Needed?

Which Repairs can Fix the P2135 Cod?

You will be able to determine what repairs are needed if you complete the steps below. Below are some repairs you might be able to make your car roadworthy again. 

• Throttle position sensor replacement
• Replacement throttle body actuator
• Sensor for the accelerator pedal position
• Fix damaged wiring
• The throttle body calibration
• Reconnect electrical cables

Common mistakes in diagnosing P2135

When faced with the P2135 code, many people simply replace their throttle bodies. 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. It could be simply a bad connection. 

How do you 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. Although every technician will handle it differently, there are some steps that you may prefer.

1. Verify all engine codes. 
2. Check the codes, then drive the vehicle and see which DTCs have been added.
3. Use freeze frame data to determine what’s going on.
4. Look at manufacturer Technical Service Bulletins (TSBs) to see if there’s anything listed by the automaker related to the problem. 
5. Examine the wiring to make sure there are no damaged connectors. The throttle body wiring and the accelerator pedal wiring should be checked.
6. To determine if there is an error code, calibrate the throttle body. 
7. You can inspect all the wires and connectors if they are good. You will find the procedures and specifications for the throttle body position sensor as well as the pedal position sensor in the manual. 

Repair cost for P2135 estimated

Once you’ve been through the appropriate steps, you have an idea of what you need to get back on the road. Below are the common repairs we recommend and their costs, based on labor and parts. 

• 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

The P2135 Code: Mechanics Tips

Don’t ever unplug the throttle body unless absolutely necessary. You will be required to retrain the vehicle if this happens. 

Sometimes you may be able to do it without a scanner. A scan tool is required for most relearn tasks.

READ MORE: Cleaning a throttle body (10 Easy DIY Steps)