[iqraceworks]

I was driving to work this morning....cruising down the road at around 50mph. All of a sudden the car goes into limp/no-boost mode and flashed the 1/2 engine icon. I stopped at a gas station and pulled the codes.....it's showing the 2E69 Knock-Sensor Signal 2 code. I reset it, and never had any other issues the rest of the way to work. I got on the gas hard a few times...no issues.

The car has fresh plugs and coils, and I just filled up with a fresh tank of 93 fuel (running MHD Stage2 91 tune). I've never had this code before....just a fluke? Bad gas? Other?

[iqraceworks]

From what I've found online.....the 2E69 code is showing that knock sensor itself is bad, and/or the wiring to it.

It's not detecting knock (as in bad fuel, or too much timing).

Does that sound correct?

[b92]

I had this code recently, turned out a mouse chewed through the knock sensor wiring. PITA to fix since you need to remove the intake manifold, but a quick solder & heat shrink remedied the issue.

Pic below. The bird seed and acorn shells on the side of the engine block are what brought me to the mouse conclusion, I'm basically Sherlock Holmes.

[iqraceworks]

Well, I had planned to pull the intake and clean the valves.....so at least I will already have the intake off.

[b92]

Originally Posted by iqraceworks

Well, I had planned to pull the intake and clean the valves.....so at least I will already have the intake off.

Good time to do that! I was going to do the same but they didn't look bad, it had only been 18 months and less than 10k miles since I last cleaned them. Added the pic to my last post.

[iqraceworks]

Would it be a good idea to reset the knock sensor Adaptations before I start thinking about replacing sensors and/or wiring? I think I can do that with MHD.

[b92]

Originally Posted by iqraceworks

Would it be a good idea to reset the knock sensor Adaptations before I start thinking about replacing sensors and/or wiring? I think I can do that with MHD.

Wouldn't hurt, but I don't think it would fix anything since your 2E69 code isn't really related to that.

2E68 & 2E69 codes are caused by the ECM not getting a reading from the knock sensors, so either a knock sensor has gone bad or there's a wiring issue. I had purchased a new knock sensor before I took off the intake manifold and discovered the broken wire, so I just returned the knock sensor to FCPEuro for full price minus cost of return shipping (which was minimal since I'm one state over from them).

[iqraceworks]

It must either be a bad connection, or faulty sensor (like everyone has said). I put about 100 miles on the car today, and never had the fault pop up again.

Very odd.....I hate intermittent issues like this.

When the senors go bad....do they just die all together, or can they give funky/bad/no readings intermittently?

[feuer]

I have a harness from 2010MY if you end up needing to replace it

[iqraceworks]

Originally Posted by feuer

I have a harness from 2010MY if you end up needing to replace it

Good to know, thanks!

[iqraceworks]

Well.....drove to work today again....no knock faults. Strange.....

[b92]

Originally Posted by iqraceworks

It must either be a bad connection, or faulty sensor (like everyone has said). I put about 100 miles on the car today, and never had the fault pop up again.

Very odd.....I hate intermittent issues like this.

When the senors go bad....do they just die all together, or can they give funky/bad/no readings intermittently?

Mine would come & go, but it eventually got to the point where the code would come up every time I drove.

[iqraceworks]

Originally Posted by b92

Mine would come & go, but it eventually got to the point where the code would come up every time I drove.

So far it's been several days....and I haven't got the fault again....just that one time. Maybe it was just a fluke?? I will keep an eye on it ...if it does it again, it must be a wiring or sensor issue.

[streetpro]

I am having the same issue, it comes on after 70-200 km, once restarted it runs fine for no matter how long (even 500 km)... sometimes it stays off for months/couple of thousands of km and then it is back on... I will replace the sensor once I take the manifold off for cleaning...

[Paz11]

Guys I’m having the same issue/issues and it’s driving me full blown mad. Keep getting 2e68 and 2e69 along with 3100 (limp mode). I’ve replaced knock sensors twice now, once out of a parts car and the second time direct from bmw dealership. Still pulling codes almost instantly after driving/cruising. Sometimes after I pull the code 2d2e for throttle valve angle- intake manifold vacuum. Are these related? I’ve tested the wiring and all seems to be correct and working. Brand new knock sensors from bmw must be good. What next??? The DME is a msd80 but appears in perfect working order. Help!!!

[b92]

Originally Posted by Paz11

Guys I’m having the same issue/issues and it’s driving me full blown mad. Keep getting 2e68 and 2e69 along with 3100 (limp mode). I’ve replaced knock sensors twice now, once out of a parts car and the second time direct from bmw dealership. Still pulling codes almost instantly after driving/cruising. Sometimes after I pull the code 2d2e for throttle valve angle- intake manifold vacuum. Are these related? I’ve tested the wiring and all seems to be correct and working. Brand new knock sensors from bmw must be good. What next??? The DME is a msd80 but appears in perfect working order. Help!!!

How far back did you check/test the wires? Could be a broken connection further upstream. The other code you're getting isn't directly related system-wise, however the wiring for that would be alongside the knock sensors' wiring.

[Paz11]

Originally Posted by b92

How far back did you check/test the wires? Could be a broken connection further upstream. The other code you're getting isn't directly related system-wise, however the wiring for that would be alongside the knock sensors' wiring.

I tested from the sensors and harness all the way to the dme. All seemed correct and fine. Figured it would have been my sensors actually failing but after going brand new from bmw I don’t see the sensors being the issue. Is there anything else possible to check or something I’m missing?

[b92]

Originally Posted by Paz11

I tested from the sensors and harness all the way to the dme. All seemed correct and fine. Figured it would have been my sensors actually failing but after going brand new from bmw I don’t see the sensors being the issue. Is there anything else possible to check or something I’m missing?

I also doubt it's your sensors since you've replaced them twice. I'm not sure where to go from here, I don't have a great understanding of how the sensors send signal to the DME so I'm not sure what else there is to do in terms of troubleshooting.

[Paz11]

Originally Posted by b92

I also doubt it's your sensors since you've replaced them twice. I'm not sure where to go from here, I don't have a great understanding of how the sensors send signal to the DME so I'm not sure what else there is to do in terms of troubleshooting.

Most have pointed towards a new dme for troubleshooting afterwards, but my dme appears to be working completely fine. I’ll continue to do tests and diagnosis and post back here if I can find a fix. Any help greatly appreciated.

[iqraceworks]

*update*

Well, it's been a few weeks and several hundred miles.....no more knock faults. Must have just been a fluke??

[Bimmer_Engineer]

Originally Posted by iqraceworks

*update*

Well, it's been a few weeks and several hundred miles.....no more knock faults. Must have just been a fluke??

It’s not a fluke...mine was behaving just like yours when it first started. It took over a year for it to transition from the first instance to almost every day.

[streetpro]

And what is the solution/cause? Mine have been quiet for over 2500 km :-)