[TDF9]

Recently brought a 2008 328xit with a 6spd manual, 135k miles. Been working my way through backlog of repairs and maintenance, and it's time to deal with code 54c8.

So I changed the transfer case oil, but code persists.

Weirdly:
* code immediately reappears after I clear it in INPA, even before I start the car (much less actually drive it).
* and the error detail includes the mileage when the error appeared - and it's always several hundred miles before / less than the current mileage, as if the error first recorded a while back.

Questions:
1) is recalibration needed after transfer case oil change FOR MANUAL TRANSMISSION cars? (Prior posts on this left me unclear)
2) can I do this via INPA or is ISTA the only way?
3) I recently replaced front driveshaft (on its last legs) - relevant in any way?
4) what to make of the immediate recurrence? I understand the error code results when the target voltage doesn't pass through the t-case oil... but is that even measured before the car starts?

Thx!

[Leucosticte]

Originally Posted by TDF9

Questions:
1) is recalibration needed after transfer case oil change FOR MANUAL TRANSMISSION cars? (Prior posts on this left me unclear)
2) can I do this via INPA or is ISTA the only way?
3) I recently replaced front driveshaft (on its last legs) - relevant in any way?
4) what to make of the immediate recurrence? I understand the error code results when the target voltage doesn't pass through the t-case oil... but is that even measured before the car starts?

Thx!

1. Yes recalibration is needed after a transfer case oil change, there is a service function for it.
2. I did it via ISTA because of the nice translated GUI, it might be in INPA as well but I haven't looked through INPA.
3. I don't see how that would affect things.
4. Could be some other problem with your transfer case, unfortunately I'm not sure, but other posts suggest it could be the resistor.

Hopefully that helps

[TDF9]

Originally Posted by Leucosticte

1. Yes recalibration is needed after a transfer case oil change, there is a service function for it.
2. I did it via ISTA because of the nice translated GUI, it might be in INPA as well but I haven't looked through INPA.
3. I don't see how that would affect things.
4. Could be some other problem with your transfer case, unfortunately I'm not sure, but other posts suggest it could be the resistor.

Hopefully that helps

It does - thank you!

[gbalthrop]

Originally Posted by TDF9

... 2008 328xit with a 6spd manual...code 54c8.
* code immediately reappears after I clear it in INPA,
even before I start the car (much less actually drive it).

Here is the BMW Fault Code Lookup Definition of 54C8:
54C8 | VTG: Classification resistor | vgsg90 | Transfer box
I have NOT had an issue with the Classification Resistor, but I attach ScreenPrints of each for my 2007 328xi;

1) INPA > VGSG > F5 Status > F4 Resistor Classification; ScreenPrint shows properly-working Resistor.

2) ISTA > VTG > Diagnosis Scan > Classification Resistor > Read State

I attach an ISTA ScreenPrint of the VGSG/VTG SSP wiring diagram, with Location of the Classification Resistor.
Please let us know what your INPA screen shows for the Resistor. You could have a wiring or connector fault, or an
issue with the resistor itself. Here are links to replacement Resistors:
https://www.getbmwparts.com/oem-part...00-27107557345
https://www.ecstuning.com/BMW-E91-32...h/27107557345/
George

[dav9515]

how common are transfer case issues on the E9X?

[TDF9]

Originally Posted by gbalthrop

Here is the BMW Fault Code Lookup Definition of 54C8:
54C8 | VTG: Classification resistor | vgsg90 | Transfer box
I have NOT had an issue with the Classification Resistor, but I attach ScreenPrints of each for my 2007 328xi;

1) INPA > VGSG > F5 Status > F4 Resistor Classification; ScreenPrint shows properly-working Resistor.

2) ISTA > VTG > Diagnosis Scan > Classification Resistor > Read State

I attach an ISTA ScreenPrint of the VGSG/VTG SSP wiring diagram, with Location of the Classification Resistor.
Please let us know what your INPA screen shows for the Resistor. You could have a wiring or connector fault, or an
issue with the resistor itself. Here are links to replacement Resistors:
https://www.getbmwparts.com/oem-part...00-27107557345
https://www.ecstuning.com/BMW-E91-32...h/27107557345/
George

This is incredibly helpful. Thank you. I will plug in my laptop this weekend and see what INPA shows

[TDF9]

Originally Posted by TDF9

This is incredibly helpful. Thank you. I will plug in my laptop this weekend and see what INPA shows

My INPA readings to not match yours, but I'm not sure how to interpret my readings ("2 Klasse C" and "8 Klasse J") - I'll attach screen shot of overview, and INPA detail of the error code. I appreciate any further thoughts, although may just try replacing the resistor and seeing if that helps.

(Will also confess I have no sense of the importance of this error, what the impact is of a broken or out of spec resistor is on transfer case performance - does anyone here know?)