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Check Engine Light Truck Reduced Engine Power or Stalling - Code P2135

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Check Engine Light Truck Reduced Engine Power or Stalling - Code P2135

Created on: 2020-08-04

This video shows you how to diagnose a problem with your throttle body position sensors with a check engine code P2135.

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So, you have a check engine light, you scan it, and then you find that you have a P2135. That's what we're gonna talk about in this video. Now, what that code has to do with is the throttle body. It's a correlation code. Basically, there's two sensors in the throttle body that those sensors are not reading the same and sending the signal to the computer of the vehicle and causing the code. When you get that code, the potential problems could be the throttle body itself, it could be in the connector or the terminals, it could be in the wiring, or it could go all the way to the PCM or the engine computer. Now, let's explain what the throttle body does.

Now, the throttle body is connected to your intake. And when the engine is running in the vehicle is at idle, the throttle blade right here is just gonna be open just a little bit. And this is what's gonna allow air to get into the engine. And when you need to accelerate, the throttle blade itself is gonna open. When you step on the pedal, that sends a signal to this motor, which is gonna turn this blade which is gonna allow more airflow to go into the engine. Now, the computer needs to know how far the throttle blade is actually open. And there's two sensors in here that send a signal to the computer. And if those sensors are not correct, or don't agree with each other, if the voltages are skewed, then you're gonna end up with that code. So, with the scan tool hooked up and the key on, we want to view the TAC data. So, we wanna scroll through and find TP sensor one, which is throttle position sensor one, and then TP sensor two, which is throttle position two, and then sensor one and two. So, here we have sensor one, here we have sensor two. Now, the values are not gonna be exactly the same, but the important part is as the values increase that they match increasing the same. And that's what sensor one and two agree says.

Now, different vehicles are gonna have different data that you can look at. Now, this happens to be a GM vehicle, so this shows the two voltages. Now, the voltages are not exact, which is exactly how it's supposed to work. So, as I press on the accelerator, if I do it nice and slow, you're gonna see the values are gonna change. And they should change equally. And as long as this says, agree, then that's good. If it does not say agree, then there's something wrong with it. So, we can actually graph this so that you can see it. I'm just gonna let it stabilize for a minute. And then if I just step on the accelerator pedal slowly, you just wanna see that these are both going at the same rate, which they are, and just push the pedal all the way down and just hold it. And if you saw one of these sensors spike, that's an indication that there's something wrong with that sensor.

Now, under the hood, what you can do with the scan tool, you can watch the data as you actually wiggle the wires and just see if any of these values change, see if that agree goes to disagree. You don't wanna unplug the connector while you're doing this, but a little bit of change is not a big deal. But if you see significant... If you were on the graph and you saw something spike, drop down, then that's an indication there's something wrong with that. So, or while you're doing this also, you could have someone pushing on the pedal and moving those readings. And what you can do is disconnect the connector and just take a look at it, see if anything looks corroded, see if there's... Sometimes if someone puts dielectric grease on this and it's not the correct dielectric grease, you could actually cause a code. There is high voltage dielectric grease and low voltage for a computer type system. So, if it was the wrong one, that could cause a code. But if you don't see anything there, a lot of times, the most common problem is in the sensor itself. And sometimes the sensors are replaceable, but most of the time, it's just easier to replace the whole throttle body.

So, for this particular issue, cleaning the throttle body is not gonna fix the issue. It is always a good idea to clean the throttle body. Although this is an extra one, this is just a spare part, you really don't wanna open the throttle blade like this manually. You could ruin the internals through that. Although when you're replacing some of the sensors, sometimes it's required to open this up while you take this off. But again, it's sometimes easier to just replace the whole thing. If you were to clean this, just use a brush and some throttle body cleaner to clean it. You never wanna take those screws out either. This throttle blade is always laser calibrated in there and you don't wanna take that out. Unfortunately, it's gonna be hard to diagnose a code like this without a proper scan tool. You can check the connector and visually look at the wires. Other than that, you're gonna need a scan tool. Hope you enjoyed this video, I hope it helped you out. If it did, make sure you subscribe to our channel, ring that bell, turn on all notifications so you don't miss any of our videos.

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