[martensoflandmark]

Hi All,

I recently purchased a 2007 335xi, just hit 100K. I have a 54C8 code that has appeared. It also seems to coincide with the symbol for brake fluid coming up as service needed (symbol in red) on my dash. This issue may also coincide with getting the orange check engine light on my dash while driving in sport mode (at about 4000-5000 rpm).

From what I can see the 54C8 code is a transfer case code, possibly revealing that the fluid needs to be changed or that the transfer case clutch plate engagement might be out of spec.

I'm just wondering if anyone has any insight into this. Will changing the fluid be the first step to see if that rectifies the issue? Or is this something where BMW will need to calibrate something with the transfer case.

Is it advisable not to drive the car with this code? I haven't encountered the check engine light since the first occurance a few days ago.
Any info/insight would be much appreciated.

[Bimmer_Bro]

Originally Posted by martensoflandmark

Hi All,

I recently purchased a 2007 335xi, just hit 100K. I have a 54C8 code that has appeared. It also seems to coincide with the symbol for brake fluid coming up as service needed (symbol in red) on my dash. This issue may also coincide with getting the orange check engine light on my dash while driving in sport mode (at about 4000-5000 rpm).

From what I can see the 54C8 code is a transfer case code, possibly revealing that the fluid needs to be changed or that the transfer case clutch plate engagement might be out of spec.

I'm just wondering if anyone has any insight into this. Will changing the fluid be the first step to see if that rectifies the issue? Or is this something where BMW will need to calibrate something with the transfer case.

Is it advisable not to drive the car with this code? I haven't encountered the check engine light since the first occurance a few days ago.
Any info/insight would be much appreciated.

The brake fluid light is just a mile timer, it has nothing to do with your other issue.
I don't believe there is any sensors for transmission fluid replacement either. It is a good service to get done although a little expensive. You may want to have a shop view this code at the same time.
are you running same size tires front and rear? Or are you a staggered set up?

[martensoflandmark]

Originally Posted by Bimmer_Bro

The brake fluid light is just a mile timer, it has nothing to do with your other issue.
I don't believe there is any sensors for transmission fluid replacement either. It is a good service to get done although a little expensive. You may want to have a shop view this code at the same time.
are you running same size tires front and rear? Or are you a staggered set up?

Thanks for the feedback. It's not the transmission fluid, it's the transfer case fluid that I am referring to.

I'm running a staggered setup on the car, you think that is somehow related?

[Bimmer_Bro]

Originally Posted by martensoflandmark

Thanks for the feedback. It's not the transmission fluid, it's the transfer case fluid that I am referring to.

I'm running a staggered setup on the car, you think that is somehow related?

Transmission/transfer case is all connected. The whole pan gets dropped and replaced plus new fluids. (Sleeves and solenoids are extra if you go that route)

You can ONLY run a staggered set up on a xi if the front and rear tire circumference is within 1% of each other. If it is not within 1%, it will cause damage and premature wear of the transfer case clutches + excessive heat.

What are your front and rear tires sizes ?

[martensoflandmark]

Originally Posted by Bimmer_Bro

Transmission/transfer case is all connected. The whole pan gets dropped and replaced plus new fluids. (Sleeves and solenoids are extra if you go that route)

You can ONLY run a staggered set up on a xi if the front and rear tire circumference is within 1% of each other. If it is not within 1%, it will cause damage and premature wear of the transfer case clutches + excessive heat.

What are your front and rear tires sizes ?

Thanks for the info. In your opinion. would you do a whole transmission fluid change rather than just the transfer case oil?

I thought the tire setup on the car was factory but perhaps not?
front: 225/40/18
rear: 255/35/18

I think that's within 1%.

[Bimmer_Bro]

Originally Posted by martensoflandmark

Thanks for the info. In your opinion. would you do a whole transmission fluid change rather than just the transfer case oil?

I thought the tire setup on the car was factory but perhaps not?
front: 225/40/18
rear: 255/35/18

I think that's within 1%.

That is within 1% so that's great!
The transfer case / auto trans is one unit. The filter is actually built into the pan of the transmission/transfer case. So the whole pan gets replaced and the fluid. Some member do the sleeves and solenoids in there too. I just had a shop do the pan filter and fluid. I got 3 quotes in town and they were all around 1400. Might be different where you live.
You are due if you haven't done that yet. Might be a good idea and they can scan and figure out your tcu code at the same time.
Once you have your issues sorted and service done, I highly recommended stage 3 xhp. It will transform your car for the better.

[Bimmer_Bro]

When you get the check engine light at 4500, does it throw it into limp home mode? (Reduced power until the car is shut off).

[martensoflandmark]

Originally Posted by Bimmer_Bro

When you get the check engine light at 4500, does it throw it into limp home mode? (Reduced power until the car is shut off).

I believe so. It only happened once but that sounds like what it could have been.

[martensoflandmark]

Originally Posted by Bimmer_Bro

That is within 1% so that's great!
The transfer case / auto trans is one unit. The filter is actually built into the pan of the transmission/transfer case. So the whole pan gets replaced and the fluid. Some member do the sleeves and solenoids in there too. I just had a shop do the pan filter and fluid. I got 3 quotes in town and they were all around 1400. Might be different where you live.
You are due if you haven't done that yet. Might be a good idea and they can scan and figure out your tcu code at the same time.
Once you have your issues sorted and service done, I highly recommended stage 3 xhp. It will transform your car for the better.

Okay, I'm totally in the dark, what is stage 3 xhp?

[Bimmer_Bro]

Originally Posted by martensoflandmark

Okay, I'm totally in the dark, what is stage 3 xhp?

Give it a quick Google but it's a tune for your transmission. 50% faster shifts, adds throttle blips on downshifts, lots of custom options.
You have to buy the licence and then the stage map you want. It will transform your car. Do some reading on it. Just like MHD, you can flash with your phone with the apps. The MHD wireless dongle works best.
I realized I just said a lot of things you are probably unfamiliar with but they are all super popular so google or YouTube it

[martensoflandmark]

Originally Posted by martensoflandmark

I believe so. It only happened once but that sounds like what it could have been.

Any comment on this? Thoughts?

[martensoflandmark]

Originally Posted by Bimmer_Bro

Give it a quick Google but it's a tune for your transmission. 50% faster shifts, adds throttle blips on downshifts, lots of custom options.
You have to buy the licence and then the stage map you want. It will transform your car. Do some reading on it. Just like MHD, you can flash with your phone with the apps. The MHD wireless dongle works best.
I realized I just said a lot of things you are probably unfamiliar with but they are all super popular so google or YouTube it

Thanks, I really appreciate all this info. I think I have a little idea of what you're referring to (I've heard some others make mention of this). I'll spend some time looking into this. From your perspective, the transmission fluid change should be done before all this though? I assume to make sure the transmission is operating as close to peak performance as possible?

[Bimmer_Bro]

Originally Posted by martensoflandmark

Any comment on this? Thoughts?

Does it trigger if you stomp on it? Right after the kick down?
Could be a misfire from a bad spark plug, coil pack. Injectors can also be troublesome on the older models.
Could also be a boost leak if you're not meeting boost target. This is all just guessing. You will need to scan the ecu to see the proper code.

[Bimmer_Bro]

Originally Posted by martensoflandmark

Thanks, I really appreciate all this info. I think I have a little idea of what you're referring to (I've heard some others make mention of this). I'll spend some time looking into this. From your perspective, the transmission fluid change should be done before all this though? I assume to make sure the transmission is operating as close to peak performance as possible?

No problem happy to help.
Yes exactly. Just a good preventative measure. My car shifted smoother after for sure.

[martensoflandmark]

Originally Posted by Bimmer_Bro

Does it trigger if you stomp on it? Right after the kick down?
Could be a misfire from a bad spark plug, coil pack. Injectors can also be troublesome on the older models.
Could also be a boost leak if you're not meeting boost target. This is all just guessing. You will need to scan the ecu to see the proper code.

If I understand, you're saying that a code reader won't tell you enough details, you need to have the ecu scanned? I'm assuming that can only be done by BMW? Just to be clear: the orange check engine light is still related to the 54c8 code or do you think they are separate issues?

[Bimmer_Bro]

Originally Posted by martensoflandmark

If I understand, you're saying that a code reader won't tell you enough details, you need to have the ecu scanned? I'm assuming that can only be done by BMW? Just to be clear: the orange check engine light is still related to the 54c8 code or do you think they are separate issues?

How did you discovery that was the code?
Are you getting a check engine light or a 4x4 light?
These transmissions are complicated but can handle a lot if cared for properly. You may want to take it to have the transmission service done and the code checked out. Choose a shop that's familiar with BMWs

[martensoflandmark]

Originally Posted by Bimmer_Bro

How did you discovery that was the code?
Are you getting a check engine light or a 4x4 light?
These transmissions are complicated but can handle a lot if cared for properly. You may want to take it to have the transmission service done and the code checked out. Choose a shop that's familiar with BMWs

Yeah, there a couple shops that are familiar with BMW's that I know. I discovered the 54c8 when I ran codes after getting the orange check engine light. I don't have any of the other lights, like the 4x4 light appearing. That's why I'm a little confused.

[drawz]

Originally Posted by Bimmer_Bro

The transfer case / auto trans is one unit.

Originally Posted by Bimmer_Bro

Transmission/transfer case is all connected. The whole pan gets dropped and replaced plus new fluids. (Sleeves and solenoids are extra if you go that route)

This simply isn't true on these cars (or any BMW as far as I know). They are physically connected, but not one unit by any means. The transfer case has its own fluid, controller, etc.

[Bimmer_Bro]

Originally Posted by drawz

This simply isn't true on these cars (or any BMW as far as I know). They are physically connected, but not one unit by any means. The transfer case has its own fluid, controller, etc.

You're right! My bad .. I thought the transmission fluid change also involved the transfer case .
So guess I have serviced my transmission and both diffs. Still original transfer case fluid with no apparent issues.

[torrque]

Guys, transfer case is separate. It has separate fluid, and a separate controller. You can change the fluid (only takes 1qt) and you need to reset the case once you do so. It will reset it to adjust to the new fluid. I did it on mine with ISTA+.

54c8 - This code gets set commonly when the actuator clutch in the T-Case has a problem. It means that the value of resistance the actuator needs to fully engage the T-Case is different than what it actually took. The common reason is that the case has not been serviced and needs new fluid. Another cause is that the connection to the servo is corroded and the motor does not get full voltage.

In your case, I would start with a fluid change, and reset. If it comes back, it's time to look for a transfer case.

Good luck.