New owner of an e53 4.8is with issues :)

[Peezen]

Hi there,

I recently bought a 2004 4.8is to by winter ride and it came with a host of issues, most that I knew about, and it was priced accordingly. I have a 91 850i and my wife has an Z3 and an LR3 for work, and I do all repairs myself, so you get the picture lol!

I have done a tonne of reading on the various codes I’m getting but nothing like a clear picture, and form plan of attack, so I figured I’d join you all in here and ask for some help/advice

Here are the symptoms I have so far:

- Front axle drops fast when SAV is off
- trifecta lights all on (4x4, brake, ABS) all yellow, and tire pressure light as well
- self levelling suspension inactive message on display (will not go into extended or access via the switch)
- when driving, it will drop itself into a fail safe setting and there is next to no power. There are no visual warnings, I notice when it happens when I step on the gas.

I have a Schwaben/Foxwell bmw code reader, a Creader, and INPA. Here are the pertinent codes:

Transmission:

-51AF: signal from transfer case faulty
-4F7A: No message from transfer case

ABS:

-5E24: front left wheel speed sensor
-5F39: transfer case

VTG:

-54C6: oil wear
-55C8: no message from DSC
-55C9: no message from DSC

There was also a steering angle code 9 on the LWS ECU. Not sure if it’s related.

Things I have done/PO did:

The PO replaced the transfer case actuator with a brand new one, a cheap Amazon one from what I can tell. I removed it and has a look and it does look brand new. I had a look at the TC module and it looks brand new, safe under the back seat. I have replaced the TC oil with factory fluid. I have ordered a new front left wheel speed sensor, and a new front air spring.

I ran some live actions on the ABS and could hear the pump work, and I ran a test in the TC actuator and could hear it functioning as well.

From the looks of it the transfer case is not communication with the ABS module or the transmission, this could be the reason that limp mode is being activated. Conversely, the TC seems to be having an issue getting info from the DSC, so perhaps that is shutting it down, which in turn affects communication back to the ABS module and the transmission. Could a faulty wheel speed sensor cause all of that?

Seems like a circle here but Inhave to start somewhere. Anyone had this group of codes before? The trifecta seems to point to either the ABS or the transfer case from what I have read and I have codes for both!

Any help or direction would be greatly appreciated

[EODguy]

A few things to start with...

Not in transport mode is it?
Check your classification resistor and transfer case motor.
Ride height sensors not flipped over?

Congrats on the 4.8iS and don't forget to add yours to the 4.8iS section by ViN

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[andrewwynn]

Recently there were two separate shorted O₂ heater situation that killed power to the EGS. See if there is a similar situation with the transfer case.

Did you say the TC was swapped out just the actuator?

Either way check all the wires going to the TC it feels like a wiring/connector issue.

[c-bass]

I've read on more than one occasion people having issues with a brand new aftermarket actuator motor so I wouldn't completely rule it out.

[Peezen]

I knew had I had come to the right place! Thanks so much so far

To answer questions so far:

It was in transport mode actually, though I put it in that mode myself with the Foxwell somehow, I used INPA and turned all of it off as per another thread in here. No more transport mode.

The resister classification is listed as ‘L’ if I’m getting that right from the live data. It matches the letter code from the other two secotions.

Which direction are the arms supposed to point? They are pointing down I believe, but will double check.

Just the actuator was swapped, looks 5 minutes old. The PO said that he swapped it to fix the lights but it didn’t work. Are there any other wires going to the TC beyond the resister and actuator harnesses? I can make the actuator activate through live testing.

I agree that it could still be the actuator. It was a words story from the PO, he told me that he replaced the gears in the actuator and that they were all chewed up, but when I took the actuator off to have a look at it, it’s brand new and aftermarket… seems weird that the gears would need replacing on a new actuator, and there was zero evidence of tampering.

[andrewwynn]

He first replaced the gear that didn't work so he replaced the whole motor.

You are getting errors that say literally "there is no connection". Connection = wire so you need to root out which wire doesn't connect.

I would find out which connector goes from the TC to egs and test continuity on each pin. Not just there is continuity on each line but make sure no cross connection.

My transmission connector likes to regularly get water in and shorts out the pins and I need to open it up and clean it out. Maybe similar happening on your TC connector.

I changed the TC on a 328xi I think it's fairly similar but I can't recall exactly how many connectors.

[Peezen]

That’s the weird thing, we had a chat specifically about the actuator and he specifically said that he only changed the gears. Anyways, I wasn’t worried as I figured on fixing whatever arises. After all I just sold a RR P38 that I restored, and I own an e31 850i, a Z3, and an LR3 that all need my attention from time to time lol!

I did notice yesterday that the transmission wire connectors were soaked in oil from an above valve cover gasket leak. I plan to clean those up today.

I’m not exactly an electronics guy per se, but I do have some equipment. When I testing continuity are we talking matchin the wires from let’s say the actuator wire harness to the control module, or just using a volt meter on each prong?

Thanks for the help so far, I did seem pretty clear that there is a wiring issue somewhere!

[andrewwynn]

Yep extra long test leads and a helper. Any luck reach wire separate color. Test between wires that part is a little time consuming you have to test from each of every other with unplugged make sure no conduction

[EODguy]

Ah, yes. Transport mode....

I still get a hard time from the wife over the Zamboni incident.

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[Peezen]

I have dug a little deeper today. I found a lot of water on the passenger side rear under the carpet.

Here are the live data readings from the VTG:

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I’m not seeing too much going on here, not that I know to much about electronics. I does appear that the control module for the transfer case is able
to communicate though.

Is it possible that an issue with the ABS/DSC has caused the TC to stop functioning and is putting he truck into fail safe mode? The only firm code I’m getting is no signal from the front left wheel sensor.