Trailer Stability Assist stuck on

[mijango]

Hi
I towed my camper trailer on the weekend (up to Hawk's Nest, NSW) and as usual unhitched the trailer on Friday night and setup camp.

We went for a drive on Saturday and I noticed the gearing was slightly different (holding 1st for longer) and that the parking sensors weren't working. I am pretty sure the car still thinks the trailer is attached as is in Trailer Assist mode

I've since come back home with the trailer and unhitched again and still the problem remains.

Any ideas how to fix?

[discotwinturbo]

Weird.

I would try a hard reset first.

Brett..

[Basil135]

Have you (or someone else) installed a trailer module for LED's?

If so, it is either locked into the on position, or gone faulty.

Another alternative, is that a short has occurred between earth & the indicator circuit in the socket.

[mijango]

Thanks guys.

I have fitted in line resistors to the indicator circuits on the trailer, but that was a good 6 or so months ago and til now they've worked perfectly.

If I was to do a hard reset, firstly are there any downsides in doing this, and also how do I do that?

[discotwinturbo]

Thanks guys. I have fitted in line resistors to the indicator circuits on the trailer, but that was a good 6 or so months ago and til now they've worked perfectly. If I was to do a hard reset, firstly are there any downsides in doing this, and also how do I do that?

No downsides that I am aware of.

Pop bonnet. Put hand brake on and close doors. Wait for hand brake light to go off. Remove negative terminal than positive (if you have a dual battery system that feeds back into the starter then you will need to disconnect it too). Use a metal rod or spanner to short the battery cables...not the terminals.

Reverse for reconnection, positive them negative.

See if that fixes it.

If not...you have a short likely in the car trailer connection.

Brett....

[mijango]

So I first checked the trailer for any shorts (just checking that all the various signals and brake lights work) and all seemed ok.
I hooked up the trailer again, and disconnected it, just to see if it would magically remedy itself .. but alas

So then tried the hard reset, but again no joy. The hard reset meant I had to reprogram the clock and also the one-touch 'up' for the windows.

So got it booked in with Ayers Automotive to diagnose. I keep telling myself that'll be cheaper than having my wife reversing it into something

[sniegy]

Have you checked fuses?
Be the first place to look..

[mijango]

I just tried checking the fuses and strangely can't find one for the trailer stability assist. I checked all the other fuses that are related to the trailer tho.

Furthermore, Ayers Auto have had the car today and are originally diagnosed the problem to be in the TSA loom. They have now replaced the trailer module and spent 5hours diagnosing only for me find out problem still remains.
They did mention it was fixed (ie parking sensors working) tho when my wife reversed it out of the garage, the sensors stopped working again.
$840 for nowt!! Grrr..

[LandyAndy]

Thanks guys.

I have fitted in line resistors to the indicator circuits on the trailer, but that was a good 6 or so months ago and til now they've worked perfectly.

If I was to do a hard reset, firstly are there any downsides in doing this, and also how do I do that?

Check your resistors for loose or broken connections.
We have a Mercedes prime mover at work,the wiring has failed twice in the last couple of weeks,once on the indicator circuit and once on the reverse beeper circuit.The truck has resistors fitted due to LED trailer lights.When the resistors are faulty you can here the computer looking for the issue when its parked ans ignition off,the faulty resistor makes a clicking sound,much like a shorted electric fence.May not be your issue but worth a look see.May only click when you open the drivers door so get a helper
GOODLUCK
Andrew

[Graeme]

As I understand it, the only definite information is that the rear parking sensors aren't working when they should be. I would persue a probable wiring fault with the sensors, possibly behind the bumper. I would take it back to where it was attempted to be repaired to ask them to have another look because I would expect some warranty on the work done. My D4 had an intermittent fault caused by a short circuit on a sensor wire that had rubbed on metal.