L322 to Cape York

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Originally Posted by Graeme

A switch in the BCU wake-up wire to the suspension ecu that can be switched off after selecting off-road height but before connecting the trailer might be worth trying. This could initially be tested by switching the engine off at off-road height and waiting 15 seconds after the last door is closed before connecting the trailer to see if the vehicle lowers. The manual states "when the wake-up signal is removed by the bcu, the air suspension ecu powers down" so may not request/respond to canbus messages regarding a trailer.

Edit: BCU wake-up signal wire is pin 38 (red with yellow stripe) of the large suspension ecu connector and likely either 5V or 12V analogue.

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Next time that I have a trailer handy I will give that a try

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Originally Posted by Graeme

A hard-wired Llams kit would allow off-road height in normal mode but even though it costs less than the plug-in kit for MY07 onwards, it still seems an overkill. I assume there is not an option to select/deselect using an appropriate diag tool.

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Uteman asks what is a Llams kit?

Llams modifies the 4 height sensor signals to provide off-road height plus a few variations depending on switch settings whilst the suspension ecu thinks the vehicle is at normal height, mostly used to overcome the 50 kph off-road height automatic lowering in D3/D4/RRS vehicles. Its available as a plug-in kit to any LR with the Terrain Response version of air suspension but due to lack of suitable connectors has to be hard-wired to earlier L322s.

Have a look at an IIDTool from GAP Diagnostic.

Home - GAP Diagnostic

You can reset all heights to new heights. Just raise std height to new level. Can restore after.

Good luck with the trip.

Gary

Uteman I got the Gap IIdtool exactly for this purpose initially and it did the trick. It's since paid for itself many times over with the reading/resetting....

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Originally Posted by flyboy

Uteman I got the Gap IIdtool exactly for this purpose initially and it did the trick. It's since paid for itself many times over with the reading/resetting....

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It seems that you have probably done some off-roading with a trailer as we now want to. I am getting a little old to be sleeping on a 1" thick matress so looking for more comfort so will be towing a camp trailer in future.

I still prefer the 'freedom' feeling of not towing a trailer....but I now have two kids on the back seat, 2 big dogs in the back and can't jam everything onto the roof.
I'm looking forward to one day getting back to 'Bear Grylls' style with just a flint and a swag!.....and a Range Rover

Quote:

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Originally Posted by Graeme

A switch in the BCU wake-up wire to the suspension ecu that can be switched off after selecting off-road height but before connecting the trailer might be worth trying. This could initially be tested by switching the engine off at off-road height and waiting 15 seconds after the last door is closed before connecting the trailer to see if the vehicle lowers. The manual states "when the wake-up signal is removed by the bcu, the air suspension ecu powers down" so may not request/respond to canbus messages regarding a trailer.

Edit: BCU wake-up signal wire is pin 38 (red with yellow stripe) of the large suspension ecu connector and likely either 5V or 12V analogue.

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I noticed that If I connect a trailer when the car is at off road height, the car will stay there. But the 50km limit applies and once it goes to std height it locks in.

Graeme, what about a switch on the iBus wire from the trailer ecu? If the trailer ECU is off the iBus then the rest of the car won't know about the trailer.
* I don't know if the trailer lights will still work - If there is no Bus does the trailer light module shut down?. I'm pretty sure the trailer ECU gets light signals from the LCM on different lines.
* It would need to be a good quality switch

I've spliced a USB port into the iBus wire at the trailer module for navCoder ect, so I know it is easy to find.

Personally I use IID, have different setting saved. IID is not as convienent as LLams for this purpose.

I only have the wiring schematic for the suspension ecu, with no information on the rest of the vehicle.

According to RAVE there are 7 wires to the trailer ECU
Battery - from rear fuse box
Earth
iBus (UNY - blue/brown/yellow) data lines are always 3 colour in BMW
Tail RH – from LCM
Tail LH – from LCM
Brake – from LCM
Ind LH – from LCM
Ind RH – from LCM

Light Check Module (LCM)
The LCM provides signal inputs to the trailer ECU as follows:
Rear Fog Lamp
The rear fog lamp function of the trailer ECU is controlled via a bi-directional data line
between the LCM (C2040) and the trailer ECU (C0380) on a UNY wire. When the trailer ECU
receives a rear fog lamp signal, it provides a feed to the trailer socket (C0499) on a YR wire.
Reverse Lamp
The reverse lamp function of the trailer ECU is controlled via a bi-directional data line
between the LCM (C2040) and the trailer ECU (C0380) on a UNY wire. When the trailer ECU
receives a reverse lamp signal, it provides a feed to the trailer socket (C0499) on a YU wire.

RH Tail Lamp
When the LCM (C0937) detects that side or headlamps have been selected, it provides a
feed to the trailer ECU (C0380) on an SP wire. The trailer ECU (C0380) will now provide a
feed to the trailer socket (C0499) on an SR wire.
LH Tail Lamp
When the LCM (C2040) detects that side or headlamps have been selected, it provides a
feed to the trailer ECU (C0380) on an SW wire. The trailer ECU (C0380) will now provide a
feed to the trailer socket (C0499) on an SB wire.
RH Direction Indicator Lamp
When the LCM (C2039) detects that a right turn has been selected, it provides a feed to the
trailer ECU (C0380) on a UN wire. The trailer ECU (C0380) will now provide a feed to the
trailer socket (C0499) on a UY wire.
LH Direction Indicator Lamp
When the LCM (C0937) detects that a left turn has been selected, it provides a feed to the
trailer ECU (C0380) on a UG wire. The trailer ECU (C0380) will now provide a feed to the
trailer socket (C0499) on a UR wire.
Brake Lamps
When the LCM (C0937) detects that the brake pedal has been pressed, it provides a feed
to the trailer ECU (C0380) on a BU wire. The trailer ECU (C0380) will now provide a feed to
the trailer socket (C0499) on a BW wire.

From what I read, the iBus provides reverse and fog light input to the trailer ECU, and relays bulb out messages (which is displayed as “CHECK TRAILER LIGHT”) and trailer connected messages from the trailer ECU.

I just don’t know if it trailer lights will still work without iBus – tipping they will.

Also would be very easy to make a box to replace the trailer ECU, you would loose the bulb checking functions, which can't handle LEDs anyway, so you would no longer need a shunt box for LEDs and you would enable height changes with a trailer on.

What happens if the iBus connection to the trailer ECU is switched off? What could possibly go wrong, might give it a try on the weekend.