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Check Engine Light Camshaft Position Sensor Circuit High Input - Code P0343

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Created on: 2020-07-02

This video explains the code P0343, and shows you how to diagnose and repair it.

So you have a check engine light and you pull the code. You find that you have a camshaft position sensor code P0343. That's what we're gonna talk about in this video.

So I built this model specifically for this video, so you can see what the internals are doing. So you have a crankshaft, which is at the bottom, and that's connected to the pistons, they are going up and down. And then there's also a timing belt. Sometimes there's a chain in different vehicles and there's a camshaft at the top. And the camshaft, as it spins, it opens and closes the valves to let in air and fuel and let out the air and fuel into the exhaust. So as this is moving, just like that.

So what this sensor actually does is monitor the camshaft as it's spinning. It tells the computer where it is and where it's orientated so that everything works smoothly.

So majority of the time, the actual cam sensor is what the fault is. And on this 2005 Chevy Tahoe, the cam sensor is actually located behind the intake. It's very difficult to reach, but I can actually grab the connector and try to disconnect it. I have the engine cover off.

Here's the connector itself, and the sensor is way in the back of the engine block.

This is what the camshaft position sensor looks like. That is for this vehicle. Now something between this camshaft position sensor or the connector or the wire or even the PCM, the computer, is not seeing a signal. So this is why we're getting a check engine light. This can also cause an extended crank. When you go to crank the vehicle, it may take longer for the engine to start.

So with a scan tool or a code reader that has ability to look at data, engine data, we're gonna look at the cam sensor high to low and low to high. With the engine running and the cam sensor not working, the values are not changing. Even if you graphed it, you can see that they're not moving. It's not counting up, which is what it's supposed to do. When the engine's running these numbers should be counting.

So this is what it should look like with the engine running and the cam sensor working properly. The values are gonna go up. If you graph this, you can see as the vehicle runs, the values are going up. So that's what a good sensor looks like.

All right. So we have the connector disconnected right here. Now we have the red wire, which is the positive wire. So the computer is gonna send its own battery positive to this connector, and then the black and pink wire is gonna be the ground. And then the brown and the white wire on the end is gonna be the signal wire. So what we can do is we can take a meter, multimeter, put it on voltage, and you want it on DC voltage. Now we can check between the pink and black wire and the red wire, and we should see 12 volts there.

And right there we have 11.3 volts, which is good. This battery is not really up to par, which you want to make sure your battery is good and charged to do any of these tests. Now that's what the key on we have that, so we know when we have good, positive and our ground.

Now, if I took a test light and went between the pink and the black wire, just use a little wire or a terminal, and then also went to the red wire, the test light lights up, then you know you have good power and ground.

So that confirms that the wire's good, the connector's good, and the computer's working properly. In that case, you need a sensor.

So as long as your wires tested all good, chances are you just need the cam sensor. After you replace the cam sensor, clear the engine light, drive the vehicle. You should be good to go.

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