Disco 3 (LR3) D3 Suspension Fault Codes - Help Please

Picked up a 140,000m Disco 3 late last week and I love it. I made a quick post https://www.landyzone.co.uk/land-rover/bought-a-disco-3-yesterday-haaaalp.363876/#post-4975362 to outline the problems I was seeing, including the suspension bottoming out and hopping, then working just fine! Then going ping and disappearing. On the advice of @lynall I went out and bought a second hand code reader on eBay.

I got the iCarsoft i930 as it seemed to have most of the functions I needed.

Just this minute I went out to the car and did a full scan. A few odd errors on systems like the speakers (?) but I am happy to ignore those for now.

The test can be split into 2 parts. The first where I read the codes as they presented the first time. I took photos of each and I shall go through these in a moment.

Then part 2, I cleared the original codes, took the car for a 10 minute drive, put the suspension up and down and up and down and did a lot of braking and swerving and then took another set of code readings.

To a novice like myself I was pleased to note the errors all appear to be coming from a single source. A little worried that when I did the first reading there were only 4 codes, yet on the second where were about 10. However, the second set all mentioned one component which I thought was interesting. So here we go!

Part 1 Codes: (First plug in, as I found the car)
Error 1/5: C1A74 Rear left height sensor mechanism - status - current
Error 2/5: C1A05 Rear left height sensor - status - current
Error 3/5: C1A07 Cross articulation - status - current
Error 4/5: C112F Air spring valve - status - current
Error 5/5: C1130 Air spring air supply - status - current

So I cleared all the DTCs, took the car for a drive, no warnings or lights and the suspension worked a charm.

Stopped and did another reading:

Part 2 Codes:
1/5: C1A74 (Again) Rear left height sensor mechanism
2/5: C1A05 (Again) Rear left height sensor
3/5: C1A07 (Again) Cross articulation
4/5: C112F (Again) Air spring valve
5/5: C1130 (Again) Air spring air supply

However, there were these additional codes under new categories, different codes but all with a similar message: Each was under a different group including ABS, SRS, Ride level control module and All terrain control module.
1/2: U0132 Lost communication with ride level control module
2/2: U0421 Invalid data received from ride level control module

1/1: U0132 Lost communication with ride level control module

1/1: B1B78 System pressure

1/1: U0421 Invalid data received from ride level control module

As one can see, the invalid data error was reported by 4 different systems, but all using the same code. I have no idea if this is significant.

In terms of a solution, I spoke yesterday with Paul, my friend who runs the garage. He pulled a face and muttered something unflattering about Land Rovers, but then agreed for a small payment in beers we could treat it as a personal project for me and we would spend a few evenings getting this stuff sorted out. I must be clear however that while he is genuinely an extraordinary mechanic (27 years) who knows his stuff, he has not done anything like this on a LR...so any explanations will need to be simple please?

Can anyone suggest what we start with first? My aim is to just buy second hand on eBay or similar, at 140,000 miles I don't see the added value in spending on original parts new, by way of a quick example a second hand genuine compressor pump on eBay is listed for just over £100, with the same thing brand new from the local LR for nearly £800. I must be honest I just don't have the budget as much as I would wish I could buy new from the original manufacturer. If anyone can make any recommendations for a good alternative manufacturer or part that will be very, very helpful thank you!

Looking at the codes, it would appear that the Rear LH height sensor on the blink.
However it's also coming up with other codes related to the suspension system, so the fault might not be where indicated by the codes. Wiring is a common issue on these.

Generally HDC codes are related to a failing battery, where the voltage drops just a bit low on cranking (the D3 needs a battery capable of putting out at least cranking 800 Amps), if codes are to be avoided on a cold morning.

To be honest. If you don't have the budget to drop at least a Grand or more on repairs per year, then a D3 isn't the vehicle for you.

They are about the least reliable and most expensive vehicle to own.

Yes they are nice to drive, and appear good value second hand, but they're cheap for a reason. Maintaining them is far from cheap, even if a good quantity of second hand parts are used.
An example of this is from my own experience.
My D3 was a 1 owner, full dealer history, with 130k on the clock. It came with a massive file of paperwork to prove just how much it cost the previous owner. In the first 8 years of it's life, before my ownership, it had spent on it almost £23,000 on normal maintenance and repairs.

Once I took ownership of it, I continued to maintain it correctly, which consumed another £3,500 of my own money in 3 years, and I did the spanner work.

These are expensive and needy vehicles, and when things go wrong, they go wrong big time. For instance it's very common for the crankshaft to fail out of the blue, requiring a engine replacement. Another common fault is a bracket on the oil pump that holds the timing belt idler pulley breaks off, allowing the belt to slip and bend valves.

So be warned, these vehicles are normally very expensive to own, which is why I don't own one now.

AMK pump, but does not sound like pump/compressor is your issue.
800 quid is just plain mad, 100 quid just wont last, but lets be hoenst if money is tight and it only lasts a year, then so what just buy another one, needs must and all that.

The wiring close to the sensors themselves is a potential failure point, and you can get new plugs with a short piece of loom to replace them.
If your man has a scope he can test the sensors.
Or the carsoft might be able to see sensor status? in which case it might show which corner is the odd one out

The wiring itself like all modern cars is thin, to bloody thin and does not take knocks well.
If you lift the suspension to off road height, and take a look pasenger side rear behind wheel on top of the chassis rail behind a small plastic cover you will find two largish plugs and you are bound to find some repaired wires, they tend to rub through on the metalwork, I lined where they touch on mine with neoprene foam.
I can recall recnetly reading about some wiring mod done when the cars were current, and that approved mod/repair was tucked up above the compressor (again handily passeger side rear just in front of the wheel) what it was for I cannot remember!

Sensor plug kit, unsure if correct part, ie you need to physically check with yours, three wires so will be something like 5volt in, variable voltage output, and an earth/return, https://www.ebay.co.uk/itm/Discover...855053&hash=item341e148431:g:K6AAAOSwL05eF09g

Nodge68 said:

Looking at the codes, it would appear that the Rear LH height sensor on the blink.
However it's also coming up with other codes related to the suspension system, so the fault might not be where indicated by the codes. Wiring is a common issue on these.

Generally HDC codes are related to a failing battery, where the voltage drops just a bit low on cranking (the D3 needs a battery capable of putting out at least cranking 800 Amps), if codes are to be avoided on a cold morning.

To be honest. If you don't have the budget to drop at least a Grand or more on repairs per year, then a D3 isn't the vehicle for you.

They are about the least reliable and most expensive vehicle to own.

Yes they are nice to drive, and appear good value second hand, but they're cheap for a reason. Maintaining them is far from cheap, even if a good quantity of second hand parts are used.
An example of this is from my own experience.
My D3 was a 1 owner, full dealer history, with 130k on the clock. It came with a massive file of paperwork to prove just how much it cost the previous owner. In the first 8 years of it's life, before my ownership, it had spent on it almost £23,000 on normal maintenance and repairs.

Once I took ownership of it, I continued to maintain it correctly, which consumed another £3,500 of my own money in 3 years, and I did the spanner work.

These are expensive and needy vehicles, and when things go wrong, they go wrong big time. For instance it's very common for the crankshaft to fail out of the blue, requiring a engine replacement. Another common fault is a bracket on the oil pump that holds the timing belt idler pulley breaks off, allowing the belt to slip and bend valves.

So be warned, these vehicles are normally very expensive to own, which is why I don't own one now.

Click to expand...

Hi Nodge and thank you for the reply and insight.
I just sat in the garden with the girlfriend and read out your reply and with that the whole project has come to a grinding halt. The reason for the desire to be strict about costs is because we recently began a new company and times are very uncertain, so taking on another burden of thousands simply does not make sense. The road tax on the car is £600 a year...so it was never going to be a cheap ride. We accept this. But to a point.

The plan was to tinker and use a friends facility to help keep costs down, but if what you are saying is right then this will be an endless, bottomless pit and really represents horrible value. And for us at the moment no matter how romantic a notion and how much I love the brand, its irresponsible to take it on. Our plan is to send it back to Auto Trader, where we were made aware of the errors but not the specific codes, and now that we have them it sounds like it's going to be thousands. And I just can't put thousands into a car right now with all the other risk going on. Pity though. I cannot hide my disappointment.

Pooglet said:

Hi Nodge and thank you for the reply and insight.
I just sat in the garden with the girlfriend and read out your reply and with that the whole project has come to a grinding halt. The reason for the desire to be strict about costs is because we recently began a new company and times are very uncertain, so taking on another burden of thousands simply does not make sense. The road tax on the car is £600 a year...so it was never going to be a cheap ride. We accept this. But to a point.

The plan was to tinker and use a friends facility to help keep costs down, but if what you are saying is right then this will be an endless, bottomless pit and really represents horrible value. And for us at the moment no matter how romantic a notion and how much I love the brand, its irresponsible to take it on. Our plan is to send it back to Auto Trader, where we were made aware of the errors but not the specific codes, and now that we have them it sounds like it's going to be thousands. And I just can't put thousands into a car right now with all the other risk going on. Pity though. I cannot hide my disappointment.

Click to expand...

If you have other financial commitments, then you don't want a D3 causing you any additional financial hardship.

I loved my D3, and at the time I needed the 7 seats and height with a disabled and terminally ill dad. However after the need for such a vehicle past (unfortunately dad passed), I sold the D3 for what I could get for it, returning to a smaller and more reliable Landrover.
I always have an Landrover, and love the mark, but I am well aware that the large LRs, although amazingly capable vehicles, come with an amazing appetite for cash.

I've now moved on to the Freelander 2, which is 3/4 of the Discovery 3, but with only 1/4 the running costs.

lynall said:

AMK pump, but does not sound like pump/compressor is your issue.
800 quid is just plain mad, 100 quid just wont last, but lets be hoenst if money is tight and it only lasts a year, then so what just buy another one, needs must and all that.

The wiring close to the sensors themselves is a potential failure point, and you can get new plugs with a short piece of loom to replace them.
If your man has a scope he can test the sensors.
Or the carsoft might be able to see sensor status? in which case it might show which corner is the odd one out

The wiring itself like all modern cars is thin, to bloody thin and does not take knocks well.
If you lift the suspension to off road height, and take a look pasenger side rear behind wheel on top of the chassis rail behind a small plastic cover you will find two largish plugs and you are bound to find some repaired wires, they tend to rub through on the metalwork, I lined where they touch on mine with neoprene foam.
I can recall recnetly reading about some wiring mod done when the cars were current, and that approved mod/repair was tucked up above the compressor (again handily passeger side rear just in front of the wheel) what it was for I cannot remember!

Sensor plug kit, unsure if correct part, ie you need to physically check with yours, three wires so will be something like 5volt in, variable voltage output, and an earth/return, https://www.ebay.co.uk/itm/Discovery-2-SLS-Air-Suspension-Ride-Height-Sensors-Harness-Connector-Repair-Kit/223842960433?fits=Modeliscovery|Plat_Gen:MK+III&epid=1215855053&hash=item341e148431:g:K6AAAOSwL05eF09g

Click to expand...

Hey Lynall and thank you again!

I just confess the reply from @Nodge68 at the start has put a real downer on this. Your original post was that I should brace for over a grand just for the struts never mind the suspension has been on my mind.
My business is in the automotive sector and while I am not involved in the maintenance side, the work I do sees about 15 cars a week go onto Paul's garage so he really does owe me personally and was quite willing to do the work. It would not end up costing me anything for the time and trouble, but I would obviously be required to source the parts. In my mind it was going to be fun. But not if this is just step one of a 200 step journey and each one is going to leave me with a £1,000 nosebleed. Then I need to be a grown up and think about it.

I'll chat to Paul when he puts on the new tyres, later this week and we can see how we proceed, but for now it would seem the whole thing is going to be a wash. Pity.

Another evidence that iCarsoft is a weak generic toy as it doesnt show the full code which includes a subcode too just the generic 5 character code(it's explained in the "DTC index"), anyway, based on the code description you might figure out the exact code and you have instructions for each code in the attached doc. Good luck

Pooglet said:

Hey Lynall and thank you again!

I just confess the reply from @Nodge68 at the start has put a real downer on this. Your original post was that I should brace for over a grand just for the struts never mind the suspension has been on my mind.
My business is in the automotive sector and while I am not involved in the maintenance side, the work I do sees about 15 cars a week go onto Paul's garage so he really does owe me personally and was quite willing to do the work. It would not end up costing me anything for the time and trouble, but I would obviously be required to source the parts. In my mind it was going to be fun. But not if this is just step one of a 200 step journey and each one is going to leave me with a £1,000 nosebleed. Then I need to be a grown up and think about it.

I'll chat to Paul when he puts on the new tyres, later this week and we can see how we proceed, but for now it would seem the whole thing is going to be a wash. Pity.

Click to expand...

To be fair Nodge speaks the truth, even though he does own a freelander

Sadly they started to get very complicated when the p38 came out, even before that they were not simple, but at least the parts were cheap.
This is not specific to just land rovers, all vehicles are going the same way, we want tech/power/toys, and they give them to us.

It cannot hurt to get Paul to do a little, and maybe enjoy the car for a short period of time, you know chuck some cheap tyres on, adjust the tracking to sort of compensate for the worn susp bushes, the problem now is even parts are not cheap for any make of car.

I have read many a thread where someone has bought a late model high tech car for the max credit they can raise, then either the engine or gearbbox goes bang, so they have to borrow even more money to get it repaired, on that 15k car that was overpriced in the first place, so now the 15k car owes them 20 plus k!

lynall said:

To be fair Nodge speaks the truth, even though he does own a freelander

Click to expand...

Someone has to own a Freelander!

I spoke from my own experience with a D3, and several other owners of them, who's I look after. Don't get me wrong, the D3 is a brilliant vehicle when it's good. However it can throw an absolute curve ball, normally at the most inopportune moment. This is why I suggested that already being financially stretched with a new business, and buying a D3, particularly one with issues, isn't the best way forward. When you have a new business, you need to concentrate on the business, not plow time and money into a vehicle.

lynall said:

Sadly they started to get very complicated when the p38 came out, even before that they were not simple, but at least the parts were cheap.
This is not specific to just land rovers, all vehicles are going the same way, we want tech/power/toys, and they give them to us.

Click to expand...

Absolutely. With all modern cars (not just LRs) it's always sensible to have a sizable contingency fund, because the law of sod will guarantee that if the worst can happen, it will happen.

I decided that after 3 1/2 years and 50 k miles, that I couldn't really be plowing £1200 odd into a vehicle, that was loosing at least that amount in depreciation per year, so we parted ways.

I then bought a cheap FL1 and drove that for 4 years, on a very tight budget, which allowed me to save for the FL2 I now have. I don't regret selling the D3, but I do miss it sometimes.
However once I've got the FL2 up to the same standard that I got the D3 too, I know I'll be just as happy with the FL2, and it's cheaper to maintain/run so it's a win win all round.