Rear height sensors not communicating

[Discobeaver]

Gday guys just needing some help with some faults I am chasing.
Decided to finally take it up the bush a couple of weeks ago, was pretty impressed at how it went until we stopped for a bit. Looked back at her and noticed the rear at full height and the front at normal. Started her back up to find the orange susp. fault light on dash. Tried the selector switch to no avail , but then flicked the high low switch by mistake at which point everything really went down hill. The transfer went to Neutral and stayed there. Tried hard reset Nanocom reset all failed. after going through connectors resets for an hour or so we gave up and tried towing her out. Long story short gave up after some winching etc and checking what was up ahead the easy way out. Before giving up and leaving it there I pulled the transfer selector motor out and managed to get it into low range manually. From there managed to drive home ( about 40 klms away ).
So after checking connectors wiring etc and trying a second hand transfer ecu for a couple of weeks Im ready to give up.

Transfer - Pulled shift motor manually put to High looks ok if i trying clutch calibration just goes back to neutral.Given up on this for now.
Suspension- Tried to lower back to level and managed to dump to bump stops, now cant get back up.
Showing no communication with rear sensors , have replaced all height sensors makes no difference. When clearing faults with Nanocom the compressor runs for 5 seconds or so then alarm sounds and it cuts out.
Have also replaced brake light switch checked brake lights and tried different battery.
Does anyone know if a compressor fault would stop comms to rear sensors or more likely directly related to them. Connectors so far all look clean ie ones in wheel arch etc. and havent found any dodgey wiring.
Still havent pulled central junction box out or compressor filter.

Any help would be greatly appreciated as I'm over it. Plan to do compressor next then give up and fit the GOE air kit and send it a dealer and wait for the second mortgage. Had car for year and a half done near 30000ks pulling 2 tonne and its been faultless, ready to go back to GU now.
Thanks.

05 D3 4.4v8 auto se 229000ks

[Tombie]

So you’ve had no faults.. you get one electrical issue and you want to jump ship?

There is a reason qualified mechanics exist...

A visit to an Indy would also work.. and I doubt the bill will be too bad.

[Graeme]

Get yourself a copy of the workshop manual CD from the AULRO shop. It will provide lots of information on the suspension system and prevent you from wasting more time and money unnecessarily replacing components. Don't bother touching the CJB as it wont be the cause. Analysing the fault codes combined with knowledge of the suspension system is the key to resolving the issue quickly.

[Globetrotter]

Seems you possibly jumped in without looking at what the codes meant. Do a reset (battery leads off) then power on and run engine and see what codes come up. This will give you a clue on what is maybe wrong. It may be only one thing causing your grief

[Discobeaver]

Started with fault codes hence transfer case module eg. po641 tfer case mod. sensor ref. open, u0403 invalid data from tfer case mod.Some ride level ecu faults inc. uo132 lost comm with ctrl module etc.
Also had found minor corrosion on plug pin on transfer module a while back that's why I grabbed a spare. Brake light switch, height sensors etc. just outta spares kit. Thanks Graeme have been working through Manual and searches. Wont bother pulling cjb mainly been going through plugs / wiring looking for something obvious actually all seem a lot cleaner than I thought they'd be.
Thought the fact it'd lost communication to rear sensors but not front mighta meant something but other than plug in wheel well cant pick where.
Think I'll just wait till I can get it to the dealer ,if they weren't 100ks away would have already been there.
Thanks for the help, Cheers

[Graeme]

Have you tried replugging the connectors at the suspension ecu? The ecu connector closest to the front of the car is for the rear harness but it sounds as though there's a wiring problem closer to the rear. The sensor wires connect directly to the suspension ecu, not via any other ecu.

Is a Llams kit fitted? Except for the earliest kits, the front sensors are handled by 1 IC and the rear by another so a failed rear IC could present 0V to the suspension ecu for both rear sensors. The Llams harness fits between the sensors and the suspension ecu at the suspension ecu.

[Discobeaver]

Cheers Graeme, no Llams fitted have looked at the plugs on the ecu seems ok. Will trace right through the wiring see if I can find something.
Thanks again

[Graeme]

There is a connector from the rear valve block with a wire length of 570mm heading towards the suspension module. The connector includes the rear height sensor wires. It is the only connector in that harness so if you haven't found it and re-plugged it then maybe worth finding it. The other side of the cable is over 4m long so I suspect that the harness runs along the left side of and possibly inside of the body. The connector is probably unplugged to remove the body so should be quite accessible although perhaps the connectors at the sensors and valve block are detached.

The rear harness connector can be unplugged from the suspension ecu with power still available to the ecu so that the 5V and earth ecu pins for the rear sensors can be checked. The ecu is held by a single bolt (10mm head) making it easy to demount to get good access to the back of the connectors or the pins themselves.

[RANDLOVER]

I had a similar issue, which leads me to suspect the fault reporting is a bit clumsy when presented with multiple faults, which in turn leads me to suspect an earthing/wiring problem. There is a known taped joint inside the front passenger door under the sill where a wire has been tee'd into the loom, make sure it's properly insulated, which I think can lead to cascading faults. Which could explain why the fault presents in the suspension and transfer case, although I think the "invalid data from T/case" is a common one that often pops up. My suspension fault only affected the gears, when I inadvertently turned the key on while I had the suspension module unplugged, but reset easily with the batt. lead short trick.

[Discobeaver]

Thanks for the loom directions Graeme very helpful. so after unplugging cleaning and testing found that I was getting good supply to the sensors so I tried the old ones again. SUCCESS ! Looks like I made a big mistake there changing all sensors at once. As far as I can figure only one of my front sensors was stuffed originally causing dash warning , I swapped all with the new ones I had for spares but the back 2 don't work (maybe wrong model got all as set from ebay )
End result Suspension working again . YAY . Next the transfer but not till tomorrow, not pushing my luck any further today.
Thanks heaps for the help Very very much appreciated. Had been looking at loom forward from rear sensors but it actually runs to the rear just behing valve block the through floor. Those plugs needed a good clean anyway outsides were caked in dirt.
Thanks again