Transmission fail safe..

[andrewwynn]

Wet bought two nearly identical e53 X5. We used them both as daily but it was exceedingly helpful to have a "spare parts" host at times. Pulled parts more than once to make one operational. Also as one was older I got to practice a repair on one that I would be able to fix faster on the second go.

[Themoog]

Further to my trans failsafe program..
I took the car to the transmission specialist who rebuilt the unit.

I drove the car for about 1 1/2 miles absolutely fine. No problem whatsoever until I had stopped and turned the engine off when I dropped the daughter off.

Upon restarting it went into failsafe mode which also included failure of all the instruments on the cluster apart from the fuel gauge. The temp gauge was all the way over the hot side. No speedo and no rev counter.
I maybe mistaken (due to my heater blower fault - see other thread) but the HVAC didn’t seem to respond when I fiddled with the ‘-‘ and ‘+’ for the fan either.
Everything else seemed to be working ie lights, radio, steering and seat auto wheel adjustment (I have the comfort option).

Anyway, Ian at the garage plugged in the diagnostic machine to see what’s what and all that came up were 3 modules to read. He said that there should be lots more on the display which suggests ( to him anyway) a wiring fault or body control module fault but he did say that he is an expert on transmissions, not electronics.

Thoughts or experience anyone?

[EODguy]

What 3 modules?

I would point out that the cost of a foxwell nt-510 that can stay in the car without issue (60c here) should be just fine there and then you'd have the ability to check right away without hoping that the fault repeats for your indie...

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[Themoog]

I don’t know what 3 modules. I should have took a screenshot.. Someone on Bimmerforum uk mentioned that if the temp gauge is all the way over in red it means that there is no data from the ecu. Apparently.

[RRPhil]

Is Fuse 1 okay in this fuse block? It powers the engine & transmission ECUs. (This is actually off a L322 Range Rover, but I assume the E53 is the same).




I had similar symptoms on my L322 when the thermostat heater shorted.

https://www.rangerovers.net/threads/...4/#post-421594

Phil

[Themoog]

I’ll take a look when it stops raining.. The engine is running ok - starts ok too. It’s just the other things mentioned above.
On a side note - could my hvac system cause this as I’ve noticed that although the blower motor is groaning it sometimes doesn’t run like it’s stuck or something.
Just thinking out loud.

[Themoog]

Ok, so I’ve not checked those fuses yet as it’s raining all the time. I have however, scanned the car when it was cold before starting. Only the ignition was on.
This time-
DD CAN timeout ASC/DSC
DC CAN timeout, electronic transmission management (EGS/AGS)
78 signal, vehicle speed
80 CAN BUS monitoring
82 CAN ABS/DSC signal
81 CAN timeout DME
20 wheel speed sensor front right transmits no signals
21 wheel speed sensor front left transmits no signals
68 steering angle sensor internal

Some of those may be explained as the car was stationary I’m not sure.
I took it for a drive for 30 min and it drove ok.
The heater blower motor would not work at all and the hill decent switch was illuminated and would not turn off.
No lights on the dash.
During the drive I reconnected my scanner but it would not communicate with the car at all.
Got home and switched off. When I restarted it was in trans failsafe mode with no speedo or rev counter and the temp gauge was right over in the red again.
Something is going on that I can’t figure out.
Anyone around the globe got any ideas?

[andrewwynn]

Seems you have a lot of wiring issues. Was this car ever in a flood situation?

I would pull all the connections off on the ebox and clean them with contact spray and reassemble.

I think there's a tie to can buss on the oil sensor known to short and cause problems. (not sure if it's that sensor. I had a problem in that neck of the woods once but it ended being something else so I didn't need to swap the oil sensor).

[Henn28]

So many of those symptoms are identical to those I had when my DSC module failed. Perhaps your model hasn’t failed (hence no trifecta), but there is a communication issue to/from it with a harness or connector?

My AC and blower were dead
My speedometer was dead
Transmission failsaife mode activated
Almost all of the same timeout codes were present
Pegged temp gauge
Strangely, my aftermarket backup camera that I installed stopped working. I’m assuming because the circuit/fuse I tapped off of in the trunk went dead

It would run fine for a few miles and then all the above would appear, presumably as it warmed up and something shorted internally. I didn’t have the wheel speed sensor codes though. Long odds that they both would fail at the same time. I’m still thinking your DSC module or wiring harness is failing.

I had no luck with eBay modules and had to buy a new one. Fortunately they are still available, but not cheap. Hopefully you can find an x5 or two in a junk yard and yank the modules. If in fact it ends up being the DSC module.

[Themoog]

No it’s never been in a flood.
The climate controls still light up and the led fan speed bar goes up and down but nothing from the fan.
I also noticed that when I switch the ac on and off I couldn’t detect the compressor kicking on or off and altering the rpms.
I think I need an expert..
Cambridge Uk anyone..?