dash message - trans failsafe prog (help!)

[BMW DIY Guy]

Hey yall

2001 E53 with 140k miles on it just for reference, and extremely well maintained.

Fired her up yesterday and started to back out of the garage and got the dreaded dashboard DING! and then a fault message. The reader display says "trans failsafe prog". I immediately went back into drive, and put her back in the garage. Being an IT guy, went for the "have you rebooted" option and stopped and restarted several times, but the code remained.

I pulled the ECU error code, and it is:

Current Fault Log
------------------
ECU reports no current faults

Pending Fault Log
------------------
P0763: Shift Solenoid "C" Electrical


So this sounds like a failing shift solenoid? This isn't something I am familiar with on the car. My partner also just let me know she saw like briefly, like 6 months ago while far away from home. Got the message on start, stopped and restarted the car and it went away immediately.

Lastly, the car fired up perfectly this morning and still good after a short test drive around the neighborhood.

So.. failing solenoid? Forum search didn't come up with anything, though maybe my forum-fu is weak this morning.

thanks yall, hoping something simple and easy, as timing couldn't be worse for complex and/or expensive.

[edogg]

When I got that message, it turned out to be a failing alternator - oddly enough.

[BMW DIY Guy]

Originally Posted by edogg

When I got that message, it turned out to be a failing alternator - oddly enough.

Now THAT would be weird!! Not something I would even consider..

[X53Jay4.8is]

Originally Posted by raichean

Now THAT would be weird!! Not something I would even consider..

Its actually not something that is weird because as the vehicle starts to experience any drop in voltage or current supply any number of electrical messages can start to show up. I would check the charging system first to make sure that its up to spec before digging into the transmission.

[BMW DIY Guy]

Originally Posted by X53Jay4.8is

Its actually not something that is weird because as the vehicle starts to experience any drop in voltage or current supply any number of electrical messages can start to show up. I would check the charging system first to make sure that its up to spec before digging into the transmission.

Very very true, thank you!

[RRPhil]

Hopefully, as the other guys have stated, it’s just a battery voltage issue. I assume your E53 is a 4.4i with the ZF 5HP24 transmission?

You can do a quick test of ‘shift solenoid C’, without dropping the sump, by removing the 16-pin connector on the back of the transmission



and measuring the resistance between pins 4 & 16



It should measure 26 ohms.

If there’s a problem, shift solenoid C (or 3) is the brown-coloured one on the end of the row in the sump



Phil

[edogg]

Originally Posted by X53Jay4.8is

Its actually not something that is weird because as the vehicle starts to experience any drop in voltage or current supply any number of electrical messages can start to show up. I would check the charging system first to make sure that its up to spec before digging into the transmission.

Yeah, it's not a terribly intuitive thing. But when you think about how reliant the E53 is on the electronics, it makes sense.

[BMW DIY Guy]

Originally Posted by RRPhil

Hopefully, as the other guys have stated, it’s just a battery voltage issue. I assume your E53 is a 4.4i with the ZF 5HP24 transmission?

You can do a quick test of ‘shift solenoid C’, without dropping the sump, by removing the 16-pin connector on the back of the transmission



and measuring the resistance between pins 4 & 16



It should measure 26 ohms.

If there’s a problem, shift solenoid C (or 3) is the brown-coloured one on the end of the row in the sump



Phil

Daaaaamn.. thanks Phil! Crazy specific! Thank you! I have done a fair amount of self garage work but the transmission is a scary place full of dragons and evil spirits for me still.

[jopecasa]

Originally Posted by RRPhil

Hopefully, as the other guys have stated, it’s just a battery voltage issue. I assume your E53 is a 4.4i with the ZF 5HP24 transmission?

You can do a quick test of ‘shift solenoid C’, without dropping the sump, by removing the 16-pin connector on the back of the transmission

and measuring the resistance between pins 4 & 16

It should measure 26 ohms.

If there’s a problem, shift solenoid C (or 3) is the brown-coloured one on the end of the row in the sump

Phil

Awesome mate!

Thank you for sharing!

[Delta2nineR]

I've also had this on my "06 e53 (ZF 6HP26). It always happens when the battery is low. I've got a faulty starter which drains the battery so it hasn't been started in a while I'll get this message.