Member Since: 06 Jul 2018
Location: Essex
Posts: 332
Suspension problems, or monitoring problems.
Hi Guy's
I'm slowly picking though the faults showing on my new to me D4 2012 SDV6
I have an odd situation where the suspension goes into extended mode when lowering with a fault indicated on GAP as C1A13-64 pressure does not decrease when venting gallery- Algorithm based failure- signal plausibility failure.
But I also get U0421-68 ( 28 ) invalid data received from ride level control module-algorithm based failure- event information.
Is it likely they are both cause by a faulty position indicator or a dodgy module?
I should point out that using the GAP tool I can lower and raise the suspension fully no problem so the car works but there's a monitoring problem somewhere I just cant suss out.
Any idea's on where to start he process of elimination?Disco 4 2012
9th Oct 2018 8:39 pm
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
I'll take that as a no then?Disco 4 2012
11th Oct 2018 8:52 am
jumbobrain
Member Since: 11 Oct 2018
Location: Telford
Posts: 6
I'd be checking your position sensors first. I'm sure there is a way to rule out which one is bad
11th Oct 2018 8:59 am
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
Yes, I was leaning that way. They all show movement on the 4x4 app when putting a wheel up the curb etc. But the rear near side does seem a little less willing to display movement.
I think I will change the regulator and remove the rear nearside to see if it makes any difference..Disco 4 2012
11th Oct 2018 4:08 pm
Brucey
Member Since: 24 Oct 2015
Location: Bedfordshire
Posts: 137
Hey Bazza,
I’ve got a similar fault. When I try to lower the car from off-road height while stationary I get the same error codes as you and the car goes in to extended mode.
If I lower the car while moving it seems fine.
While looking at the live values for suspension height it looks like it’s the rear that doesn’t lower. Now is that because of the rear valve block or a dodgy height sensor I don’t know!
13th Dec 2018 8:13 am
Brucey
Member Since: 24 Oct 2015
Location: Bedfordshire
Posts: 137
I’ve done a bit more work on this, yet to find a solution, but might have found the smoking gun.
I’ve just done the suspension calibration on the IID tool after noticing the right rear was a fair bit higher than the left rear (when measured). Got to say the calibration process is very easy, well done GAP. But alas this didn’t fix my problem.
Before I did the cal I was driving home and took a log of the suspension heights while driving normally, then raised, then tried to lower while stationary and finally lowered while moving. Below are some screen shots.
Click image to enlarge
Raising
Click image to enlarge
Failed to lower while stationary
Click image to enlarge
Lowered while moving
Now to my untrained eye, I’d say the RR is not behaving like the others (this is pre-calibration which is why that sensor reads higher than the others)
Thoughts?
Worth doing the same logging Bazza?
13th Dec 2018 12:29 pm
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
Hi Brucey
Yes I will, in fact I have had the tool on live readings and I have noticed one rear lowering slower than the other (on the graph). What we need to do I guess is get outside and somehow measure the movement, even if it's visually to see if the movement is the same as the graph. If it is then probably a release valve, if it isn't and the car is lowering evenly maybe the ride height sensor?
The thing most people blame is the pressure release valve on the compressor which I think is a kit fix. but depending on the age & use a number of things can go wrong with valve blocks getting clogged by the material coming out of the air dryer the dryer blocking etc. But those things would stop both sides from dropping at the same time
The other thing I did was to manually operate all the valves with the GAP II tool at which time everything worked
I will try that again next I think along with another look at the live data
If all that makes sense.Disco 4 2012
13th Dec 2018 4:30 pm
Brucey
Member Since: 24 Oct 2015
Location: Bedfordshire
Posts: 137
Yeah I agree. If it was the exhaust valve then all 4 corners would drop slow. I was wondering if it was the rear valve block, but after seeing the live data from the sensor I'm going to take a punt and buy a replacement.
Keep us updated on how you get on
13th Dec 2018 7:33 pm
Brucey
Member Since: 24 Oct 2015
Location: Bedfordshire
Posts: 137
How did you get on with this?
I finally received and changed my dodgy height sensor. The car still doesn't like lowering to access height but instead of 3 errors I just get the one now C1A13-64
20th Feb 2019 7:04 pm
moogser
Member Since: 31 Jul 2017
Location: Gloucestershre
Posts: 40
I’m getting exactly the same errors and symptoms so would be interested to know if/how you got this sorted.
Cheers,
Phil
20th Feb 2019 8:07 pm
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
Brucey wrote:
How did you get on with this?
I finally received and changed my dodgy height sensor. The car still doesn't like lowering to access height but instead of 3 errors I just get the one now C1A13-64
I've been a bit overloaded work wise for some time now so haven't moved forward with this lately. Have to report the fault is becoming more regular now and can trigger in normal driving, it also triggers instantly as the selector is pressed, but still not fully identified as yet. I've had 2 Land Rover professionals give me 2 completely different opinions both of which require starting a regime of part changing (and both certain it will fix it) It would be nice to be able to nail it down especially as there seem's to be a few people with the same problem.
Interesting re the sensor, can you remember which codes got sorted out?Disco 4 2012
23rd Feb 2019 7:20 pm
Brucey
Member Since: 24 Oct 2015
Location: Bedfordshire
Posts: 137
So the trick with diagnosing the height sensor was graphing the ride heights on the IID tool. The codes I was getting before were C1130-7A, C112F-72, C1130-66, U0421-68.
I'm not sure what to try next, if I over ride the suspension with the IID tool and manually lower the car the exhaust valve opens fine. But maybe it's not reacting quick enough for the ECU?
24th Feb 2019 4:13 am
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
Same here with the over ride.
One thing I did notice, I upgraded the brakes with some better disks & pads and when lowering the car back down off the jacks the rear shocks sounded dry as a bone and came down in creaky judders rather than a smooth progress. This opens up the possibility that the struts are stiff providing enough resistance to make the sensors think the car is beached? They operate OK on the road and stay inflated though?????
The mystery continues. Disco 4 2012
10th Mar 2019 9:32 pm
Brucey
Member Since: 24 Oct 2015
Location: Bedfordshire
Posts: 137
Yeah interesting.
Well I've just bought a service kit and exhaust valve for my Hitachi compressor. I'm hoping that sorts it for me
11th Mar 2019 6:55 am
Brucey
Member Since: 24 Oct 2015
Location: Bedfordshire
Posts: 137
Update so far...
I've just overhauled the compressor using an X8R service kit, including the aluminium end cap. I also bought and fitted one of these kits that includes the exhaust valve https://www.advancedfactors.co.uk/jpo50001...5193-p.asp
It was quite a satisfying job to service the compressor. You can remove the compressor and continue to drive the car as long as you pull fuse 26 in the engine bay.
I refitted the compressor tonight and so far so good. It makes 25-50psi more than before and it also doesn't error when lowering. I'm going to continue to test for the next week before I'm convinced it's fixed.
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