Trouble code!! 1286

[Cory1970]

I am getting a trouble code for 1286.... What could be wrong with my car???

[guinness325i]

http://autorepair.about.com/library/...l-dtcs-57a.htm
Its the Knock control test pulse.

[Cory1970]

I have been getting a code 1222 for a while (rich/lean more than 8 seconds). Take a look at my other thread to see my attempts to fix it....
http://forums.bimmerforums.com/forum...d.php?t=423282

let me know what you think

[Cory1970]

http://autorepair.about.com/library/...l-dtcs-57a.htm
Its the Knock control test pulse.

So what is the problem??

[parolof]

probably nothing wrong with the knock sensor, check the wiring/connector

[Cory1970]

does anyone know where the knock sensor is located on an m42?

[Cory1970]

ttt

[Cory1970]

ttt

[parolof]

on the engineblock under the intake manifold

[Tim Polzin]

I am getting a trouble code for 1286.... What could be wrong with my car???

I had the same code. I tried replacing the knock sensor with no change in codes. I ended up pulling the DME and reflowing solder on the PC board where the connector and main components mount. That seemed to have cured the problem.
Good luck...Tim

[parolof]

yes, the knock sensors seldom fail, it's usually a bad connection somewhere

[kalinrs]

I decided to scan my computer as well this morning. I did not have the CEL on, but decided to do so out of curiosity. Of course something showed up and it was the 1286 code. A quick reference online and Bentley showed up the knock control test pulse. In fact Bentley states faulty DME in case you get that code.

I decided to follow Tim's advice before taking out the manifold and checking sensors. I removed the DME and re-soldered the connector and most of the main components. Sure enough, as soon as I put it back I got 1444 - no fault. I did not have to reset codes. I just placed it back and did the 5 throttle pushes and got the 1444 this time.

Thank you very much Tim, you saved me lots of work and research! I will keep an eye on the CEL to see if it will show up in the future.

I also wanted to update and bump the thread in case somebody runs in the same problem.

[dozanti]

def needs to be a sticky under DIY.... this could make someone insane when all it is, is the solder by the DME connection. Nice job guys !

[kalinrs]

I just got back home from work and decided to check for codes again. Unfortunately, 1286 was there again. I guess I will be taking it out again tomorrow and doing some more re-soldering. It must be either within the DME or the cable/connector since stressing that area fixes it.

My DME looks pretty clean inside and no traces of moisture. I am pretty sure I was the first one to open it as well since the tabs that hold the case get scratched easily so you can tell if somebody has messed with it before.

Apparently it must be just regular wear and tear (vibrations) that cause it. I guess the code is not that important since CEL does not come on. I did feel a little bit of throttle response improvement, but I might be just fantasizing.

I will keep the thread updated as soon as I work on it a little more. Unfortunately I am fighting with the popular leak between my roof, windshield and door bushing (or whatever it is called). It is starting to piss me of although it is just a few drops. Better fix it before I find the car turned into a boat one morning

[jzimmer87]

If I wanted to replace the DME does it matter whether the used computer came from an automatic or a manual?