So I replaced the cam position sensors and SES light is still on. Help!

[tynash@yahoo.co]

So I went to Autozone and ordered 2 new Camo Position Sensors for $69 each and got home and with the help of e38.org tore into the job. it is very easy and only took about an hour and I was taking my time. So I put both sensors on and my wife took it out this morning and said the SES light was on again. Here is the history of the situation:

SES light comes on and is on for a day or two, then the light goes off for about a week.

Then the light is back again and I take to auto zone early this week to read the code. The code came up as P0340. A day or so later the code goes away again. It is on and off all the time. So I order the sensors from Auto Zone and install them last night and this morning the light is on, I take it to Auto Zone and it is the same P0340 code again with the new sensors!

My Questions...
Is it possible that the timing belt needs replaced?
Could the code need to be cleared from the Onboard Computer to reset the system so the computer knows the new sensors were replaced or does the car automatically know?
Any other suggestions?

Thanks again for everyones feedback and help as I try to work through this. Last resort is I get bent over by my indy to let him figure it out, but I would love to work through this on my own first.

[daverk]

I just went through the same problem as described. I ended up replacing the computer to the tune of $1,900.00 problem is solved. hope you dont run into the same problem. have the computer flashed and it should show the problem.

[tynash@yahoo.co]

Now you are scaring me. I hope it is not that.

[gmcgann]

Have you reset the computer, rather than just waiting for the light to go off on it's own? I had the p340 code, replaced the sensor, cleared the code with a code reader, and the light has been off since.

[tynash@yahoo.co]

No, Autozone never erased it using thier hand help reader. Would that make it go away for good?

[plik]

No, Autozone never erased it using thier hand help reader. Would that make it go away for good?

The computer re-checks everything every ... I don't know ... 300 miles, or so. So your check engine light will eventually shut itself off; however, in my opinion, it's best to have the good folks at AutoZone reset the thing for you.

That will make the codes go away; however, if the problem is still there, then the codes will come right back.

[kromdom]

The OBD-II is good only up to a point but you should be able to use the reader from Autozone to erase the codes.

From reading around, the MORE reliable/accurate reading comes from the port in the engine bay. PEAKE is the most popular

[BMW5868]

<TABLE cellSpacing=0 cellPadding=0 width="100%" border=0><TBODY><TR><TD vAlign=top>This may help. My vehicle is 2000 740i.

It just might be the harness side or the connector, replacing the cam sensor usually fixes it. First Clear the codes and retry, if not recheck using these steps.

* Note always use a high impedance mutimeter not a test light when checking or damage to the controller is possible. Big Bucks. Get a reasonablly priced one from radio shack or maybe autozone?

1. Cam sensor is supplied with 12-volt power and ground.


2. Unplug the connector for the cam sensor where is goes into the engine harness right front head on the motor. Next using a voltmeter with the ignition key on, probe the engine harness and measure the voltage pins 1 and 3, these are the two outer pins & should measure battery voltage.

3. Cam sensor is a hall effect switch. Next test is to check signal circuit, which is the middle pin of the cam sensor connector. Backprobe the middle pin with the cam sensor with it plugged in ignition key on. In order to do this, may need to pry open the engine harness's plastic cover to gain access to it, the cover just pops off. If using a voltmeter, turn the motor over by hand, voltage readings should read 0 V, then 5 V, then 0 V again. If a lap scope is available, crank the engine. Scope should display a clean 5 V square wave.

Possible causes:
Defective CMP sensor - replaced unlikely
Power supply - corroded or open circuit, bad ccontroller
Supplied ground - corroded or open curcuit

Hope this steers u in the right dirrection

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[tynash@yahoo.co]

THank you everyone for the feedback.

I went to AZ and they said it was against store policy to clear the code. So I said whatever and went next door to Advance Auto and they would do it. So now the code is clear and I am just going to wait to see what happens. I gotta think it will be back in the next couple days, but we will have to wait and see.

Feel free to chime in if anyone else has any other ideas.

[plik]

If you ever come across someone with a stick up their butt who won't clear your codes, then just ask them if you can borrow the code reader and they'll usually let you clear your own codes.