Multiple codes/limp mode

I can scan the ABS module. I will check if cluster to see if it is moving. How to test CAN bus?
I can check voltage levels at the throttle with ignition on.

Gauge doesn't rise when it's started. ABS codes in attachment. All engine codes attached. They can all be deleted but when i rescan again and before starting the car only the 3100 stays there. Then after restarting 2a9e and 2a9f are back, also 2acb, and 3100.

That DME relay code came back, did you have battery voltage at those fuses that are fed by the DME relay? with negative lead on the battery negative? If that relay is not being powered up, or if there is a voltage drop across the relay and there isn't full battery voltage getting to the DME then of course nothing else is going to be getting full power either.
Check fuse F70 also for full battery voltage.
Also, if you pull the DME relay out, there should be 1 pin in the relay socket that has battery power all the time. The 2E85 also is not good, that's a communications code. The coolant pump is either missing voltage or its too low for the pump. This car is having voltage issues. since you have no blown fuses that you can see, which I would recheck all of them, I'd say it's not a short to ground, but there's definitely a voltage problem. What was the reading on the DME voltage from battery? You wouldn't have this many codes without a main major issue. There aren't 10 different sensors gone bad at once.
You have to investigate source voltage issues here. Even if a fuse isn't blown, they do get hot and can slow current flow. If the terminals on a fuse are dark and burnt replace it. And go to the DME relay and check it there for battery voltage.

And what did you have at the throttle actuator for voltage readings?

To check the CANBUS network usually you would use a lab scope, but you can check the voltage readings, but this car, like all others, has multiple CAN networks. It's a 2 wire BUS that will have the two wires twisted together and when nothing is being transmitted both lines will be 2.5 volts, but when data packets are being transferred, the CAN HIGH will go to 3.5v and CAN LOW will go to 1.5v roughly. But I think you're dealing with more of a low system voltage. I don't see how you can have so many codes that keep changing as well as a code for the main relay that powers the ECM without low system voltage.
Just added 2EF5, is another code saying low voltage, 5 pic.

Since this has been the trouble car of the week for me, I haven't stopped things about this thing, i did some more investigating, and the 3100 Code can be caused by a bad Cam or crank Sensor or part of the Vanos system that controls cam timing, The 3100 is a boost deactivation code. The ECM does this due to a cam sensor or variable control solenoid issue.
The 29E2 and 29F3 codes are both for the Fuel Rail Pressure sensor circuit A, or signal back to the ECM.

The DME relay code 2ACB is related to the relay switching too slow or lagging behind and can set throttle related codes. Posting this below, maybe replacing this DME relay might be worth a try. Though I don't to throw parts at a car, at this point it's worth a try, relays don't cost much.

Also here, this may be caused by the DME relay not disengaging due to melted wires, so it can't turn off, the DME monitors this circuit and flags this code for possibly not shutting down.


So, the 3100 is not necessarily a fault, it can be due to a different fault. I will keep adding to this as I find new information tonight.
Also, I found out that the brake pad warning light should be on with the ABS codes. Not sure if it is or not.
Another thing, since you replaced the alternator, I was advised by a tech who teaches now, that the over voltage of 15.5v for a prolonged time may have damaged the battery.
More to come as I find info.

Okay, i have now gone through every code, the interesting part ive noticed is most of these codes are not present at the time of this reading. except intake and exhaust cam sensors- DME relay- and low fuel pressure sensor (so this code is referring to the low-pressure side fuel system since this car has both low and high pressure.

I found something, this one circuit feeds everything you're having codes for. Check this out, second diagram, all power feed for everything you're having codes for comes from this fuse F37, and that's fed directly by the DME relay... I think this might your issue. It may be an intermittent problem which is why the codes are not all present right now. This maybe a low power (voltage) issue at starts up or something along those lines...

Thanks for digging further. If this is the car of the week for you as a master tech imagine me dealing with this, lol. So many things to look at. I thought about the battery but again hate to throw away parts too. I only spent money so far on the alternator. I also ordered a fuel low pressure sensor since it got broken while i was checking the voltage. I can try another relay and see. The brake pad code is there yes. Am also afraid that the hpfp is what is causing all of this.

Upon doing more reading, some people state that the black relay, which is the only one in the ecu box is a fan relay, others say it's the DME relay, others say the DME relay is in the fuse box all the way to the top and right, but my box does not have one there and you can't install one, not sure if different models have different set up.

Thats what i was wondering too, i know if it's made in a different country, or from California it will have different emissions standards. But it might be the low-pressure side fuel system effecting the High-pressure pump, you can test the low side, it should be 72PSI, but the High side you have to be very careful with.
The DME relay is under the passenger side dash in the junction box. It will be in with all these fuses. below.
I see you're using a different scan tool, can you get any fuel trim numbers with that???

The fuel trims are all over the place, but connectors have ground and power. Can you look at this post which talks about symptoms just like mine and they said it was their DME relay behind the box like you mentioned.
https://www.spoolstreet.com/threads/08-335xi-dme-relay-location.6195/

what are the max the fuel trims are hitting and on short term or long term?
oh, my goodness look at that fuse box. ugly.
Try looking up the part number, that relay is upside down, so it's 19262.

Problem is i can only do it using the scanner because i don't have a valve to measure it mechanically, so hard to say, i think i have a video I will post it in few.

okay, I'd like to see the fuel trim numbers and whatever data is readable on that same screen.. I will try to get a better location for the relay, its reading that its soldered on the backside of this box just above that black relay.

You are right as far as the relay location i believe. I will take a chance. Send me a link if you find one on how to remove the box. Attached are some files.

More. Some with car off others with it running.

What was the other scan tool you were using before, the grey screen?
Those High Side pressure readings were down in the 100s. That scan tool doesn't do Fuel Trim numbers? Short Term, Long Term? it sounds really hard to start too. I think you're dealing with multiple problems.
When and how did all this start? Did you buy this at auction or something?

Grey one is a maxisys. Yes, it's hard to start. I have to turn ignition off and on 3-4 times or more for it to start. Sometimes it starts from first time. I did measure fuel trims using both scanners on other cars before and it did work.

Hang on, there's a recall for that fuse panel i think, let me get this info.
There's also info on the main battery feed into that junction box behind the glove box overheating. You may be able to get the dealership to replace that fuse panel. Because it looks like you have to solder a new DME relay in, which sounds completely unreasonable considering how many problems they cause.

Okay, it looks like this is a smart junction box, there's some programming involved if its replaced. i couldn't find much on that, but I will give you what i did find. I would think it would be easier to replace the whole box if the relay is soldered in, but you'll have to see when you get it out of there. This is for the box behind the glovebox. That idle issue may just be the High-Pressure pump failing and leaking pressure back into the low-pressure side. I've heard of that happening. That might explain why the low side pressure was all over the place. I saw it hitting 90psi at some points.
If the High-pressure pump failed though, they usually break, and pieces go into the injectors. Small particles of metal will clog the injectors up. These are Piezo Injectors too, they're not cheap.

Yes, I know the pump isn't cheap. The recall/extended warranty is for 10 years/120,000, so am out. I doubt I need to program the fuse box, but I will check again.

The reprogram is for after its replaced, I think you just need to get at that relay and see if it's the issue. Who knows what you may find back there.

Changed low fuel pressure sensor, sane results, checked for grounds and all were good. This thing is driving me crazy.

What voltage readings are you getting at the DME? Thats the only way to rule out a wiring issue. You have to load test circuits as well. you can't just look at them and say they're good. That DME relay is the main power source for all those sensors/actuators codes. You need to focus on that DME and do real testing or you're just going to end up in the same place every time. Have you even checked the voltage level at any of those fuses coming from the dme relay? I don't understand why you're just throwing parts at this without testing.
Use a 12-volt light bulb to load test power circuits, see if they can carry current. You need to if these 3 pins are getting power (load tested) and if those grounds are good. From the battery all the way to the dme.

I removed both ecu connectors, turned ignition on, fuel pump noise is continuous during the whole time. Here is what i found:

X6002: fuse 1, wake up signal, nothing
#10, 11, ground oxygen sensor:
nothing

X6003 has ground on 4 and 5
X6005, #13 dme relay: battery volts
30, ground for crank shaft exists
36, 37, 38 for throttle, nothing, i guess it has to be running

X6003, #1, 2.5v
X6003, 13, positive
X6003, #3 nothing just shows 0
X6002, #1 battery voltage
X6003, 4, 5, and 6 all ground

okay. Well, you should have left the DME plugged in and back probed the connector, sorry I wasn't clear on that. The B+ on Pin 13 with it unplugged is just the control side of the DME relays power, if that connector was plugged in with the key on that would read 0volts because it would be pulled to ground. But you're saying on connector X6003 Pin 1 you only have 2.5volts? The 2nd diagram is going to Pin 1 on X6003. That should be 12-volts all the time. Key on or off. There's an issue.
Where are you seeing X6002 fuse 1 is wake up signal?
But X6003 Pin 1 (red/Black wire) should be 12-volts all the time coming from Fuse F4 10amp.
You should test with the connector plugged in and back probe with a T-pin. Check that F4 Fuse though, even with the ECM unplugged that should still be 12-volts.

Finally found out what is going on. Fuse f78 30a someone has removed. After reading all the diagrams it pinpointed that it has to do with the B+ distribution, so checked fuses f50 and f78, i inserted a fuse in f78 and there is no revving and there is a throttle response. Turned to off immediately as the battery is drained completely and am using a jumper and until i put everything back together. Don't even know what that fuse is for.

#2 on dme terminal.

Awesome, finally found it. Thats not even a diagnostic mistake, who would have guessed that someone else took a fuse out. I couldn't find any#50 fuse either. and there is no terminal 50 anywhere I see. But that F87 was a main power feed to the DME,,, That was causing those sensors to lose power and therefore setting all those codes. But do keep an eye on that Fuse. Someone took it out for a reason, if it kept blowing on someone there may be a short to ground somewhere that's intermittent. A wire rubbing on ground due to running vibrations or something like that. Watch to see if the terminals on the fuse get dark, that will mean it's getting hot, just not enough to pop the fuse yet.
Thank goodness. I was losing sleep over this one bud.

Lol, thanks. Yes, either keeps blowing a fuse or someone removed it. But i can swear the car ran fine the first time i checked it, but i didn't buy it. Then it came back with engine announcement. I will keep an eye on it.

The DME probably lost its memory after a period of time with that circuit powered up and eventually it was seeing bad signals from the cam sensors and such, then it just lost its mind.. Glad you found it.. At least you know if that circuit pops that particular fuse that the circuit is the one going from F4 to DME Pin 2. I am wondering about the 2.5volts, but that's for another day. It's been fun...