Hi all, my truck is still off the road. it now looks to have developed earthing issues causing the HVAC, CAV, CHCM,IPC & ABS modules to report communication issues.

I looked at the front nearside (LHS) this appeared ok on initial inspection, took of the nut and clean everything up. on tightening and without much effort the stud broke off. I have repaired this with a self tapping screw as a temp measure until I get tooling needed to install rivnuts.

Inspected the Offside (RHS) and while this showed more corrosion after cleaning up and being a bit more gentle.. reattached all as was.

I'm still getting the faults, is it safe to assume that the original stud on the RHS is still to blame (ABS) i.e. corroded internally? shall I just move the earths to the screw above? or are there more places to look?

I have been looking in the WSM for an indication of all the main earthing (grounding) points but can't seem to find any for the L494 (quickly found a diagram for the old defender tho )

Thanks in advanced.... Frustrated from Warrington...  2015 4.4 Autobiography
2010 3.0 HSE 162K - Gone

As a test, run a jump lead to the battery from the earth wire point that's snapped off. You can then check whether it's the earth points or something else. If it is the earth points happy days - it's a simple fix.

Nb - just for the record, I hate the use of "truck" !

Let us know how you get on !

Why on earth could I not think of that… and I’m not being sarcastic, been getting so frustrated with i..

Thanks for the prompt.

You wouldn’t think i am a time served spark 😂(many years ago that is..) 2015 4.4 Autobiography
2010 3.0 HSE 162K - Gone

Sometimes you need a second set of eyes and a clear head !

Had exactly the same situation changing my condenser last week. Couldn’t get a nut off and spent 20 mins faffing about with it.

Took a 10 min break and came back to it and it was off in 30s.

Ok, so RHS earth moved to sensor above and lost the ABS error. HVAC is not
Communications error but misting sensor. I already
Knew I needed to replace it.. doh

Going to move to LHS (self tapping screw temp fix) and jump it to the engine bay negative terminal to see if that works.. 2015 4.4 Autobiography
2010 3.0 HSE 162K - Gone

So using SDD the faulty modules are reporting a voltage of 11.8v. When I put in a parallel earth path that increased to 12v.. (bushman style in the dark so not entirely surprised of the miniature increase.

In the morning I plan on re using the original earth points and self tapping with bolts I have as a first point of call as if I can avoid introducing a second point for corrosion if I can avoid it.

I have a rust prevention spray as well as contact cleaner on hand so will be using them liberally…

I have just remembered that sometime ago the car would intermittently lose the radio (go blank and then power back up) no alarms… I wonder if this could also be related and if so where would be the dashboard earth points? I seem to recall on a different model the were at the bottom of the A pilla, could someone please confirm. I will also search the WSM when I back inside…. 2015 4.4 Autobiography
2010 3.0 HSE 162K - Gone

Pic of SDD
 2015 4.4 Autobiography
2010 3.0 HSE 162K - Gone

Ok so update on progress made today.

Used self tapping screws for earths in same position as the old earth studs. Measured resistance between earth point and negative on the battery and both are now less than 1 ohm.

This did clear some alarms but still had bus communication alarms and a slightly low voltage being recorded for the ABS.

I disconnected the ABS plug and sprayed contact cleaner put it back and cleared all alarms, this seems to have done the trick for the ABS module..

Still having issues with the instrument cluster and Chassis Control Module.

Located the Chassis CM and pull the plugs sprayed the contact cleaner, reconnected but still did not clear..

I’m starting to run out of ideas now the below pic is of the remaining alarms with the engine running. Good voltage showing now but unsure what can be causing this..

Click image to enlarge

Hi all,

Ok so still got the warnings but have confirmed that earth is good from the abs plug to the negative terminal on the battery.

Battery reads 14v when ignition is off.

I decided to look at the live voltages using my IID. It’s strange as the below pic is showing the voltage of the PCM the spikes were when I was turning the wheels.. anyone had this before?


 2015 4.4 Autobiography
2010 3.0 HSE 162K - Gone