Member Since: 06 Oct 2011
Location: Pangbourne
Posts: 61
A Miriad of Fault Codes
I am working through problems on my Disco. I have just replaced both front lower control arms (ball joint and track rod end advisories on MOT) and thought I would tackle other problems one by one.
I had the dreaded amber light suspension fault about 3 years ago and rebuilt the Hitachi compressor. This cured problem for a bit but I still get it even now intermittently. Recently I've been getting the HDC fault special programs not available, suspension lowered, again intermittently.....!
Hmmm, I thought battery and/or alternator, however put my battery tester on battery, that was Good Recharge, 68% charged. Multimeter on alternator, 14.1v so all good there as well.
Connected up fault code reader and a miriad of fault codes came up:
U0416 Invalid data received from vehicle dynamic control module
U0156 Can't read the photo I took
P0826 Up and down switch input circuit
C1A96 Brake light switch circuit
U0132 Lost communication with ride level control module
U0001 High speed CAN communication bus
B1b74Front foot-defrost mode stepper actuator
B1b75 Front foot - face mode stepper actuator
B1b76Front left air blend stepper actuator
B1b77 Front right air blend stepper actuator
B1b78System pressure
U0401 Invalid data received from engine control module/powertrain control module
U0421 Invalid data received from vehicle dynamics control module
So I could work through all these fault codes, which may or may not be related but I am wondering, could it be a faulty relay or faulty control module somewhere that is triggering these fault codes.
Alternatively although my battery checker is showing battery OK, it is only showing 12.26v, which by my reckoning is a bit low, should be about 12.6v. It's a VARTA Silver Dynamic by the way and about 4-5 years old.
Any good tips where to start first.......? Cheapest going towards most expensive
Pete
16th May 2021 2:57 pm
Lrsg
Member Since: 10 May 2020
Location: Norway
Posts: 77
One of your faults points to the brake light switch, which is known to generate a mess of faults if it fails. So replacing the brake light switch would be my first port of call. Which is very cheap and easy to do.
16th May 2021 4:02 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4613
Forget about the "U" and "B" codes, clear all of them them and see what P & C codes come back, then go after P0826 as well as C1A96 if present. Both of these will cause your issues, so you may have a faulty brake light switch or bad connections. Same goes for the P0826, (Suspension switch) Did any liquid spill on it? Check the connections behind it. You can also monitor the operation of both the brake light switch and the suspension switch in "live values"
If the suspension amber light is coming on intermittently you need to pull the code for that to see what's happening there. In any case neither of the above should be a big issue to resolve but 68% charge isn't ideal, (12.3v). Check the battery voltage before first start of the day and see what voltage is present. yµ (idµ - eAµ) ψ=mψ
16th May 2021 4:46 pm
ofob69
Member Since: 06 Oct 2011
Location: Pangbourne
Posts: 61
All good advice, thanks guys.
I've cleared the codes, will see what pops up. I'm a bit reluctant to change battery as first resort but also realise it could well be one of the causes.
Brake light switch first...!
Pete.
16th May 2021 5:51 pm
ofob69
Member Since: 06 Oct 2011
Location: Pangbourne
Posts: 61
Brake light switch ordered
16th May 2021 6:07 pm
ofob69
Member Since: 06 Oct 2011
Location: Pangbourne
Posts: 61
Switch bought and fitted (£10.67 including post and packing and 5 minutes to fit) fault codes cleared, so far so good. Thanks for tip guys?.......!
19th May 2021 5:24 pm
ofob69
Member Since: 06 Oct 2011
Location: Pangbourne
Posts: 61
Oh , it's back again.....
Changed brake light switch and its been fine. Got rid of the high pitched squeal from rear brakes - replaced discs, hand brake shoes and pads, replaced front lower control arms including bottom ball joint as well steering arm ball joints (MOT advisories), starting to trust the Disco once more so driving down to Bath to lend to eldest daughter and fiance and the dreaded HDC Fault, system not available, suspension lowered came on. Had to stop every 10 miles or so to reset.....
I haven't got code reader with me, so going to assume new brake light switch was cheap and faulty (Britpart jobby) so ordered OEM from PowerfulUK just in case, will consider new battery, already established voltage is low but battery tester stays its OK condition, will check steering angle sensor....... any more ideas........?
Pete
24th Jul 2021 8:13 pm
lynalldiscovery
Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274
You will need to let battery stand overnight, then check voltage, dont wake car up as that will effect the reading.
if it is 12.26 volts after standing all night, then assuming there is no parasitic drain the battery has had it.
14.1 volts is not much of a charge rate either, after a long run I would say that is okay, but after starting it should be kissing 15 volts.
24th Jul 2021 9:51 pm
ofob69
Member Since: 06 Oct 2011
Location: Pangbourne
Posts: 61
Has anybody fitted a Yuasa YBX5019 battery?
Performance looks at the top:
Capacity (C20) 100Ah
Cold Cranking (EN) 900CCA
Warranty 5 Years
Any reason why I shouldn't?
Pete
24th Jul 2021 10:39 pm
ofob69
Member Since: 06 Oct 2011
Location: Pangbourne
Posts: 61
The saga continues.
I fitted a new battery in August, it was an Enduroline; spec was very good compared with price and most of the fault codes cleared up apart from the dreaded:
So I decided to fit a new compressor, replacing the Hitachi I had rebuilt a couple of years before. It was not a Hitachi but this one:
All seemed well for a few weeks until the following appeared:
This was happening infrequently, perhaps once a week and after a journey of 150 miles and the Brake and Triangle would come on together closely followed by the Suspension light, perhaps 3 seconds later.
Today it happened 3 times on a journey of about 40 miles and each time the suspension lowered.
I got home and read the fault codes as follows:
• C1B00 Steering Angle Sensor
• U0132 Lost communication with ride level control module
• P0000 NO DTC DESCRIPTION
• U0416 Invalid data received from vehicle dynamics control module
• U0421 Invalid data received from ride level control module
• C1A13 Pressure does not decrease when venting gallery
• B1b79 Local interconnection network bus circuit 2
• B1D18 Volumetric sensor circuit
• B1b70 Local interconnection network bus circuit 2
So before I rip out the new compressor and get my money back and start all over again, can anyone steer me in the right direction because this is becoming a complete pain.
Pete
1st Dec 2021 5:47 pm
Sea Raider
Member Since: 01 Nov 2016
Location: None
Posts: 4450
Any hissing from underneath the bottom of your front passenger door?
Could be a rusty and leaking air tank
also
Worth recalibrating the steering angle sensor
1st Dec 2021 6:08 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4613
Original compressors only I'm afraid as the rest are junk.
Alternatively rebuild your old Hitachi, or replace it with a new AMK but you'll need the pipe kit modification as well as the software upgrade which is in your GAP IID if you have one.
As above, recalibrate the SAS.yµ (idµ - eAµ) ψ=mψ
1st Dec 2021 8:04 pm
ofob69
Member Since: 06 Oct 2011
Location: Pangbourne
Posts: 61
Still on it guys, this is turning into an absolute marathon.
So far this is what I have done:
1. Replaced the battery
2. Replaced compressor with an aftermarket compressor
3. Removed aftermarket compressor and got money back
4. Rebuilt my old Hitachi compressor with new seals. The old seals were worn and definitely needed replacing and I assumed this would address the ‘C1A20 – Pressure increases too slow when filling reservoir ‘(which it seems to have) - 4X4 AirSeals , couldn’t recommend more highly
5. Removed Air Tank, checked for leaks, blasted and repainted it and reinstalled it – it wasn’t bad nick apart from surface rust
6. Put Disco in ‘Off-road’ mode, removed fuse and left it for the weekend – it maintained pressure for 3 days
7. Drove car and got ‘C1A13 – Pressure does not decrease when venting gallery’
8. Consulted with Andrew Dearnley, 4X4 AirSeals - (what a great bloke, couldn’t be more helpful), realised I hadn’t replaced seals for the Exhaust Valve
9. Removed compressor and replaced Exhaust Valve seals, reinstalled but still got error messages
10. Spoke to Andrew again and we decided it might be Height Sensors so replaced all four height sensors with LR parts.
So this is where I now am, with the following error messages:
I have not yet had the height sensors calibrated, my iCarSoft can’t do that but am waiting for Arkley4x4 to call me back with a date and time to calibrate the sensors – a possible cause but I’m sceptical as ride height is fine.
I have not replaced the Suspension Relay – a possibility
I have not done a complete check of the wiring for a loose/dodgy connection but had a good look so far – again a possibility
I have not replaced the seals in the Pressure Switch Valve solenoid. I have bought the seals though from 4X4 AirSeals so could do this
Does anybody else have any ideas what may be the cause of these fault codes. It is now very intermittent. I took the car out this morning with no fault codes but it is driving me nuts.
Pete
4th Jan 2022 2:06 pm
ofob69
Member Since: 06 Oct 2011
Location: Pangbourne
Posts: 61
Well I replaced the relay yesterday, it had no effect as I guessed it wouldn't........
7th Jan 2022 12:05 pm
Nutterwatts
Member Since: 12 Aug 2020
Location: Bristol
Posts: 57
Steering angle sensor
Did you calibrate the steering angle sensor?
One of the fault codes is that and that causes lots of other codes if it's not right.
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Cheapest going towards most expensive
, it's back again.....
