[BashShah]

2007 335i E90.
Replaced faulty sensors after wires melted near exhaust.

Bank 2 cleared, but Bank 1 code will not clear.
Would appreciate some advise in what to check next.

Car running rough.

[buly34]

Are you certain that you replaced all damaged wires? You could try to disconnect the battery for 10 minutes and see if the code is still present. Then maybe try to clear it again if it is still showing up

[BashShah]

Originally Posted by buly34

Are you certain that you replaced all damaged wires? You could try to disconnect the battery for 10 minutes and see if the code is still present. Then maybe try to clear it again if it is still showing up

I cleared the code multiple times, and it keeps coming back.
Initially I had codes for both precat o2 sensors, so I replaced both.
O2 sensor wires burned to metal....so wires were touching.
After new sensors were added,
Bank 2 code cleared, but bank 1 precat is not clearing.

Then I bought another sensor thinking it was bad, but still same issue.
Very bad miss fires on cold starts.
Running lean...... Code is intermittent.

Thanks for the reply.

[buly34]

Originally Posted by DarkNemesis

I cleared the code multiple times, and it keeps coming back.
Initially I had codes for both precat o2 sensors, so I replaced both.
O2 sensor wires burned to metal....so wires were touching.
After new sensors were added,
Bank 2 code cleared, but bank 1 precat is not clearing.

Then I bought another sensor thinking it was bad, but still same issue.
Very bad miss fires on cold starts.
Running lean...... Code is intermittent.

Thanks for the reply.

So then it sounds like the o2 sensors are not the issue. How many miles are on the car, have you ever done the carbon cleaning? That could be making it idle rough. Also you are not getting any other codes right?

[JuniorB]

Put it on a scanner to see if they are at least walking,those wires can also burn upwards look for clean wire,the burned wire can give low voltage.

[BashShah]

Originally Posted by JuniorB

Put it on a scanner to see if they are at least walking,those wires can also burn upwards look for clean wire,the burned wire can give low voltage.

I replaced the ENTIRE O2 Sensors......they come with Exact Size Wiring and Sensor.
so the entire o2 sensors and complete wiring to the connector on top of the engine has been replaced.

But yes, approx 8-10 Inches was totally melted due to heat.
why did it heat......I was doing something I should not have.
going uphill, in 6 inch snow, in M2 gear with Traction control off, and seriously reving the car and spinning past 4-6k rpm.

[Brandicular]

Originally Posted by DarkNemesis

2007 335i E90.
Replaced faulty sensors after wires melted near exhaust.

Bank 2 cleared, but Bank 1 code will not clear.
Would appreciate some advise in what to check next.

Car running rough.

Silly question, but did you put each sensor back in the correct bank?

[BashShah]

Yes, Each Sensor is in the Correct Location.
If that was not the Case. then it would be a lot more codes.

Carbon Cleaning was done at 80k km.
currently at 146K km.

I did something else, while car was running, I disconnected Bank 1 Sensor, and it did nothing to see if that would behave differently.....and it didn't.
nothing changed.

Thanks for the reply.

[Corno_Baldwin]

What code is persistent?

[BashShah]

Originally Posted by Corno_Baldwin

What code is persistent?

2c3f

[avocet]

check your fuses... maybe the o2 sensor shorted and caused a fuse to unfuse.

[Corno_Baldwin]

+1 on checking the fuses

Seems like it would be a fuse associated with the DME, but I wouldn't rule out O2 circuit. That being said I don't know where the fuse is located for DME.

Just did a quick search and found someone who had the same code and replaced a 30amp fuse - it fixed their problem. Hopefully your DME is ok.

[Corno_Baldwin]

Do you know the build date on your car?

Here is a wiring diagram on the O2 sensors.
O2 sensors.pdf

Here are fuse diagrams depending on build date. Says that fuse box is located under dashboard, behind glove compartment. Hope this is helpful.
Fuse locations.pdf

[BashShah]

Originally Posted by Corno_Baldwin

Do you know the build date on your car?

Here is a wiring diagram on the O2 sensors.
Attachment 1564222

Here are fuse diagrams depending on build date. Says that fuse box is located under dashboard, behind glove compartment. Hope this is helpful.
Attachment 1564220

Build Date: Sept 2006.

Fuses Near DME are all good. (under hood)
All 30 Amp fuses in Glove box are good.

I think it is time to get either DIS or INPA up and running.
or take it to dealer.
I hope it is not DME.

Could Air Leak in Vacuum cause this?

[mxchris727]

If the wires shorted, it's possible that the DME is damaged. I would scan it with DIS or ISTA and see if there are any shadow memories.

[Corno_Baldwin]

Like yourself, I certainly hope the DME isn't fried. Good luck and please keep us updated.

[hassmaschine]

Originally Posted by buly34

Are you certain that you replaced all damaged wires? You could try to disconnect the battery for 10 minutes and see if the code is still present. Then maybe try to clear it again if it is still showing up

disconnecting the battery has ZERO effect on stored codes.

[BashShah]

Originally Posted by mxchris727

If the wires shorted, it's possible that the DME is damaged. I would scan it with DIS or ISTA and see if there are any shadow memories.

Are you saying, with a proper diagnostic BMW app, it will for sure tell me, if it is DME or wiring?

Going to be doing a continuity test on all wires right to ECU today.

[mxchris727]

Originally Posted by DarkNemesis

Are you saying, with a proper diagnostic BMW app, it will for sure tell me, if it is DME or wiring?

Going to be doing a continuity test on all wires right to ECU today.

I'm not saying that it will definitely tell you what's wrong, but you may see other codes that can help diagnose the issue.

A continuity test is a great idea.

[BashShah]

Originally Posted by mxchris727

I'm not saying that it will definitely tell you what's wrong, but you may see other codes that can help diagnose the issue.

A continuity test is a great idea.

Its going to take a long time to set up DIS or anything.
Shit.

[buly34]

Originally Posted by hassmaschine

disconnecting the battery has ZERO effect on stored codes.

I Never said it did....OP said it wasn't allowing him to clear the codes. Resetting the ECU might fix the issue

[hassmaschine]

disconnecting the battery doesn't reset the computer at all. That is my point. The current "state" is always saved in non-volatile memory.

if the codes are not clearing it's because the issue is still present.