Transmission fail safe..
 

Recently the trans in my 02 4.4 has been not shifting up to 3rd. Didn’t do it all the time only occasionally.
Today it pinged and I got ‘trans failsafe’ readout on the dash. No other lights ie trifecta but it’s stuck in 3rd gear.
Scanned it with my C110 and it says-
‘DD CAN timeout ASC/DSC’ and
‘DC CAN timeout, electronic transmission management (EGS/AGS)’.
Can anyone shed any light on this?

Happened to me when water got into the connector at the back of the transmission.

Ooo. Interesting. I'll go home a check it..

Nope it's not that

The error suggests a problem on the communication line but also mentioned DSC yet no trifecta.

Is there a second wiring harness that goes to the transmission? Else check the other side of the cable where it plugs into the control module in the e-box under the hood.

There is only one big plug connector at the bell housing end of the transmission. Nothing else. It’s a ZF5hp24.
I have a gut feeling that one of the internal solenoids has failed / stuck but could be wrong.
It was rebuilt 2 1/2 years ago with a 12 month/ 12,000 mile warranty and I’ve been in touch with the place that did it. He’s happy to run a diagnostic on it and go from there but I’m running out of time.. Flying out of London later this evening for 10 days.
Thinking of the warranty- I’m not sure I’ve even done 12k since rebuild. I must check. That would be a result.

Had the similar codes and failsafe mode when my DSC module failed. However I also had the Trifecta, which I assume you don’t?

No trifecta.

With the foxwell you can monitor all the solenoids in the trans. You can also monitor the "L" lines that tell the car what gear you're in. That was the fault in my case.

Too late. I'm at Gatwick airport. It will have to wait. It's logistics that's the problem - I have to get it to the trans shop which is about 10 miles away which is oy open Monday to Friday when I happen to be busy working..
I may see if I can find someone who does mobile diagnostic to at least give me a head start.
Funny thing is that I've been considering buying a spare car so I could take the X5 off the road for a bit to tinker with it. May do some online shopping while I'm abroad.. Another X5, Porsche Cayenne maybe.... ��