750il Trans FailSafe = Absolute Nightmare - Help?

[PiperBMWe38]

Okay... this post has been a long time coming. Need some help from you guys on here if possible. I've searched the threads, and although I'm computer savvy I can't seem to find a post about an issue similar to this...

I have a 2001 750il with about 158k on it. I've had it for about 3 years, I put about 10k on it over those three years.

I drove it for a week back and forth before I bought it trying to make sure it seemed on the up and up.

Sadly only after purchasing did I drive it up the 405 incline in Santa Monica, the 2nd night after purchase and my nightmare started.

When driving up an incline (a.k.a. under load) if the trans downshifted from 5th to 4th, it throws the Trans Failsafe Prog error, and limps into 3rd gear. For the past 2.5 years I averted this issue by going into manual mode and keeping it in 4th gear. No issues. I noticed also that it would occasionally shift roughly out of park into drive or reverse, but it wasn't consistent, and I couldn't tie the issue down to cold starts, hot days, cold days, etc... it was fairly random.

I work at a BMW dealership doing sales. A few of the senior service guys I trust said, it's your torque converter. I had it repaired at a 3rd party BMW shop that does older BMW's for a few small things, and he said the same thing, it's your torque converter.

So I drove it for 2.5 years doing 4th gear up hills, no issues other than replacing a seized throttle body.

Over the 2.5 years I did notice that the Trans Failsafe was starting to happen more frequently and on less of an incline, and near the end it was doing it on fairly level roads.

Then finally my y-shaped coolant vent hose from radiator to engine burst, so it was time to finally address some long standing issues.

I did a new torque converter, coolant hoses, belts, valve cover gasket, engine mounts, 12 spark plugs, 12 fuel injectors, rebuilt the rear driveshaft coupling (it was clicking/ticking/knocking), 2 MAF sensors as I was getting the P1270 recent to that.

Yay! Or, so I thought...

Picked up the car after a few months of work, and drove it about 10 miles and when I got onto the freeway and BAM! Trans Failsafe when downshifting from 5th gear.

Called the mechanic. I must stress I think he's fairly competent, and I don't think he's screwing me, but this is getting out of control. Here's what happened next.

It must be the Valve body. Okay, we bought a new Valve body, put it on. Same result, Trans Failsafe. AUGH!

Sent the new valve body back, put on the old one again. It was at this point he gave me the bad news when removing the valve body that there was an abnormal amount of metal shavings in that area, and that his expert opinion was that the transmission was done. It could drive, but it was only going to get worse. So it was either replace it or junk the car.

I had just spent $1,000 on a torque converter, and $2,200 on the other items. So I was already $3,200 in on a car I paid $2,500 for.

So I found a low mileage JDM (Japanese) BMW 750 V-12 Trans on eBay from a seller with good history and reputation, and figured I'm this far... let's do it.

We installed the new trans, using the same new torque converter, alright. Sweet. Let's go.

Oops, Trans Failsafe.

Okay... it's your alternator. Nope.

Trans Failsafe.

That's where I am today. I'm pulling my hair out faster than it's falling out. I can't figure out for the life of me, what could be causing this issue. Has anyone had a similar issue/problem? Any help would be MUCH appreciated!

PiperBMWe38

IMG_6349.jpgIMG_6310.jpgIMG_6311.jpg54293125132__18AF0D1E-F66F-46C1-914E-93F9B2856FC3.jpg

[Timm]

That doesn't sound like any fun! What we need to know is what the error code was (and still is). As your car has carried on bunging up a TRAN FAIL-SAFE PROG error even after changing the complete gearbox then it must be something external to the gearbox.

Equip yourself with a $40 INPA setup and diagnose it yourself, let us know what the error code is and we'll have a much better idea of how to help you.....

[georgebest]

I know I'm kind of stating the obvious...but how is your battery (ies)?

[PiperBMWe38]

I'll get the code and post shortly. I replaced the small battery when I bought it, and then both batteries at the beginning of this year. Those didn't seem to effect the Trans Failsafe issue one way or the other, but I do have the typical battery drain issue all old double-battery 7's seems to have. I bought a trickle charger when I bought the new batteries and 2 weeks later was when my coolant vent hose blew. ..of course.

[aom7]

Wow, sorry to hear this. It's these intermittent issues that are so draining. I guess there's no chance it can be the wiring harness or TCU? I guess the codes, esp. if they are consistently the same ones will help.

[PiperBMWe38]

BTW Timm, I absolutely love your https://www.meeknet.co.uk/E38/Index.htm website.

Thank you, thank you, thank you for putting that together. You are a king. I just sent a PayPal donation your way today as I've poured through your website time after time since buying my e38. Didn't realize you were on the forum as well, ...of course you would be! :-) Thank you.

[georgebest]

Timm is our national treasure!

[740il97g]

Okay... this post has been a long time coming. Need some help from you guys on here if possible. I've searched the threads, and although I'm computer savvy I can't seem to find a post about an issue similar to this...

I have a 2001 750il with about 158k on it. I've had it for about 3 years, I put about 10k on it over those three years.

I drove it for a week back and forth before I bought it trying to make sure it seemed on the up and up.

Sadly only after purchasing did I drive it up the 405 incline in Santa Monica, the 2nd night after purchase and my nightmare started.

When driving up an incline (a.k.a. under load) if the trans downshifted from 5th to 4th, it throws the Trans Failsafe Prog error, and limps into 3rd gear. For the past 2.5 years I averted this issue by going into manual mode and keeping it in 4th gear. No issues. I noticed also that it would occasionally shift roughly out of park into drive or reverse, but it wasn't consistent, and I couldn't tie the issue down to cold starts, hot days, cold days, etc... it was fairly random.

I work at a BMW dealership doing sales. A few of the senior service guys I trust said, it's your torque converter. I had it repaired at a 3rd party BMW shop that does older BMW's for a few small things, and he said the same thing, it's your torque converter.

So I drove it for 2.5 years doing 4th gear up hills, no issues other than replacing a seized throttle body.

Over the 2.5 years I did notice that the Trans Failsafe was starting to happen more frequently and on less of an incline, and near the end it was doing it on fairly level roads.

Then finally my y-shaped coolant vent hose from radiator to engine burst, so it was time to finally address some long standing issues.

I did a new torque converter, coolant hoses, belts, valve cover gasket, engine mounts, 12 spark plugs, 12 fuel injectors, rebuilt the rear driveshaft coupling (it was clicking/ticking/knocking), 2 MAF sensors as I was getting the P1270 recent to that.

Yay! Or, so I thought...

Picked up the car after a few months of work, and drove it about 10 miles and when I got onto the freeway and BAM! Trans Failsafe when downshifting from 5th gear.

Called the mechanic. I must stress I think he's fairly competent, and I don't think he's screwing me, but this is getting out of control. Here's what happened next.

It must be the Valve body. Okay, we bought a new Valve body, put it on. Same result, Trans Failsafe. AUGH!

Sent the new valve body back, put on the old one again. It was at this point he gave me the bad news when removing the valve body that there was an abnormal amount of metal shavings in that area, and that his expert opinion was that the transmission was done. It could drive, but it was only going to get worse. So it was either replace it or junk the car.

I had just spent $1,000 on a torque converter, and $2,200 on the other items. So I was already $3,200 in on a car I paid $2,500 for.

So I found a low mileage JDM (Japanese) BMW 750 V-12 Trans on eBay from a seller with good history and reputation, and figured I'm this far... let's do it.

We installed the new trans, using the same new torque converter, alright. Sweet. Let's go.

Oops, Trans Failsafe.

Okay... it's your alternator. Nope.

Trans Failsafe.

That's where I am today. I'm pulling my hair out faster than it's falling out. I can't figure out for the life of me, what could be causing this issue. Has anyone had a similar issue/problem? Any help would be MUCH appreciated!

PiperBMWe38

IMG_6349.jpgIMG_6310.jpgIMG_6311.jpg54293125132__18AF0D1E-F66F-46C1-914E-93F9B2856FC3.jpg

Yea check the code. Mine actually had a similar problem. It ended up being the front passenger side abs wheel sensor. I had to put the car in sport to get to switch between some gears.

[racer2086]

Going through transmission stuff myself, but no trans failsafe message.

There are a few things over the years I have learned about that message:

1. Voltage issue - low voltage messes with these cars and frequently can cause those transmission error messages. So that's relating to your battery and charging system.
2. Fluid, filter, and fluid level - hopefully the mechanic knows the ZF filling protocol, because low fluid level can cause some weird issues. I would also recommend using the ZF fluid.
3. Electrical sensors or wiring - ABS speed sensors play a role in the transmission computer doing its thing. Additionally, there are input and output sensors on the transmission; I've read these rarely fail. Then of course, there is the wiring to the transmission. I've read of people getting water in the connector under the car, causing corrosion and connection issues. Additionally, people sometimes get water in the electrical box under the hood. That can corrode connections and cause issues.

Do you have pictures of the pan when it was dropped? Some metal is normal. Chunks of metal is not normal.

[Nanajoth]

ABS module triggered the fail safe warning on mine. When I would put it in to sport mode the gear indicator would not show.

[00Msport]

I live in your area and drive from Marina Del Rey to Woodland Hills to work everyday. I have an 740I Msport. After fighting the issue for a year. I just said screw it a couple of weeks ago and had m 5hp24 trans rebuilt. if was $4,200 which included a rebuilt torque converter.

[PiperBMWe38]

Hi guys, thank you for the responses. Hoping I can finally resolve this issue and get my baby back on the road. I miss her, and can't wait to drive her after all the other work that has been done.

The mechanic shop said 3 codes came back. The one they think is the culprit is the second one (bold)... all of this is greek to me. Any advice or insight would be GREATLY appreciated.

Photo of his code scan below...

Code Read e38 750il.jpg

1) 82 - EGS: CAN timeout ASC

2) F - EGS: Pressure Actuator EDS, total current

3) 93 - EGS: CAN throttle

[Timm]

This is slightly confusing as, although two of the above codes (82 and 93) can be cross-referenced against the BMW master list of error codes, F doesn't!

The three codes are in Hexadecimal format and can be converted to 15, 130 and 147 in standard BMW fault code format (BMW-FC)

15 = Transmission Control Module Self-Test
130 = CAN - ABS/DSC interface
147 = CAN Throttle Valve

The EGS (gearbox computer) cannot talk to the throttle body (via DME/EML) via CANBUS (a two-wire communication bus).
The EGS cannot talk to the ABS/DSC system (this is the always-failing black block stuck to the brake system's ABS hydraulic unit)
The EGS fails its own self-test - but this could be caused by the errors above

There are two possibilities

The EGS is dead - easy to change and reasonably cheap on Ebay but you must get one of the same year and model variant
The ABS/DSC controller is dead and hanging on to the CANBUS - A test could be to disconnect it - here's where it lives:

https://www.meeknet.co.uk/E38/ABS/Index.htm

No need to remove it, just disconnect it. I'm not sure if the 750i bungs up TRANS FAIL-SAFE PROG when it is disconnected, the 740i doesn't and drives as normal minus a few bits and bobs such as the speedo! I'd give that a go first, this module is well known for causing these kinds of problems.

It doesn't make sense that you have a gearbox problem, you've changed it already!

[SilverIris]

With the degree of diagnostics that has been performed already, I vote that this become the official E38 Transmission Diagnosis FAQ thread.

As for the error codes, two of them being Canbus-related and one being a timeout is a bit suspicious. In recent months, I kept receiving a timeout error on my 750IL while the tachometer quit responding and temperature gauge pegged to full hot.

It may sound odd, but have you tried pulling fuses associated with each Canbus device? Fuse F17 powers the Steering Angle Sensor and EKAT Control Module's control circuits. If you have leaking sunroof drain tubes (common issue on E38s), water can easily pool under the carpet under the front passenger seat where the EKAT Control Module is. Result is "Canbus panic" where the power cables (unfused from bottom 110AH battery) continually backfeed 12v into the Canbus lines in the EKAT harness connector by using the water as an electrolyte. On my 750IL, this flooded the Canbus system with garbage info so nothing could communicate properly. Visible symptoms were Temperature gauge pegged to Full Hot and Tachometer was dead.

Pulled Fuse F17, no more Canbus Panic and it narrowed it down to Steering Angle Sensor or EKAT Control Module. Found the EKAT module underwater because of the sunroof drains...

Also in the same area is the under seat fuse box, containing fuses F107 through F114. F108 (50 amp) feeds the ABS DSC/ASC Control Unit.

Hope that helps.

[acspecialists]

I did not see or hear it but going over the TCM connections with a fine tooth comb would be a good step. I can't remember the circumstances but my trans acted up. I hooked up INPA to get codes and it was for the output shaft speed sensor. I even went for a drive while watching the sensor. I changed the sensor which is a hall effect sensor that would have a low failure rate. That did not fix the problem. I then went through the TCM connections and cleaned them the best that I could. I have not had any problems for months.

The hardest part of understanding these cars is that everything is controlled but a computer. I came to this revelation one day when I read about how the car is started, mine occasionally does not start on the first try. When you turn the key you tell the DME that you want to start the car and if the DME is happy it will start the car. It's the same for all of the other functions, I'm not sure if any of the controls are directly connected.