Member Since: 03 Mar 2018
Location: Deepest darkest Cambridgeshire
Posts: 11
More suspension - rear valve block A1A34 - RESOLVED
I'm confused. Can a suspension expert alleviate this?
2004 TDV6 HSE with 154k miles.
Car drives fine in standard suspension mode. As soon as the height switch is moved one way or the other, there is a little suspension movement (compressor briefly runs), then orange suspension warning light comes on with the message "Suspension fault standard height only available" (or similar, can't recall the exact wording).
As posted in another thread, I have the RSW diagnostic tools from the US, so have access to reading and clearing codes, although I don't get the codes, just the word version. The only error code coming up is "right hand rear air valve"
I am making a big assumption that this error would be created by the suspension ECU attempting to signal the valves, and the right rear one not earthing or similar. My assumption may be my error, as reading the multitude suspension threads here, I cannot see a clear link between suspension requests and what the various sensors need to return an error. My older RAVE documents for D2 and Freelander seem to have error tables for each of the codes explaining exactly what occurs to create an error code, but I cannot find such a useful thing for the D3 suspension. So, the only thing I have to go on is that the error 'Rear right air valve' means the rear right air valve is not functioning!! (this has led me to replace the rear valve block so that is new.)
With that in mind, I can deflate each corner of the car, and the suspension module will pump it back up again to target heights. I can also keep hitting the suspension switch, then clear the error, and keep doing this until the car gets to access mode or off-road mode. I can then hit the switch and the car returns to standard mode. This tells me that the rear right air valve is working and receiving signals from the ECU otherwise that corner would not rise of lower. I have checked the rear wiring and there is no obvious chaffing, broken wires, or corroded connectors.
There are also no suspension bag leaks or line leaks to the valves, as the car looses no height when left.
The compressor is 2 months only and running fine, and the exhaust valve chuffs when expected.
What am I missing here? Could it be a leak in the lines from compressor/reservoir/drier to valves, and the error trips in when there is low pressure on a suspension change request, which only shows up as a valve error?
I know there are a million suspension posts on here, some with similar symptoms but none exactly the same.
Does anyone have an opinion of what to check next, or can anyone point me to a logic table that shows what events trigger error conditions?
Last edited by The_Wombat on 2nd Apr 2018 8:09 am. Edited 3 times in total
30th Mar 2018 6:32 pm
Marmoset
Member Since: 28 May 2007
Location: Cheshire
Posts: 281
My 2005 had similar but the front air valve block was at fault. It wasn't the valve block itself but one of the wires, found by doing end to end tests on them all with a multi meter, and rather than splice in a new section, I just ran a new wire for the broken wire. Might be worth checking the wiring again as I'm pretty sure my symptoms were like yours. I had feared a new compressor being require but in the end it cost me less than a few quid in materials, just a few hours in investigating it.2011 D4 SDV6 HSE
2008 D3 TDV6 HSE
2005 D3 V8 SE - left in Oz..
30th Mar 2018 9:07 pm
The_Wombat
Member Since: 03 Mar 2018
Location: Deepest darkest Cambridgeshire
Posts: 11
Thanks for that. Pondering overnight (which is sad I know - a habit that is required if you own Alfa Romeos!!) I am coming to the same conclusion.
So a question to all those suspension experts who have had, and resolved suspension control issues:
Does the electrical wiring for the rear valve block end up routing through the dreaded vulnerable area in the front NS wheel arch?
I cannot for the life of me find diagrams of where the wiring is routed. I can check continuity of the offending right rear corner wiring easily enough, and have checked all the connections and insulation under the rear of the car (2 big block connectors with sliding locks, which comes out from inside the body to the rear of the NS wheel arch and includes the parking brake module). All seems good at that end, but if there is a continuity issue I have not yet found, I don't know where the physical cables are to double check them.
Member Since: 03 Mar 2018
Location: Deepest darkest Cambridgeshire
Posts: 11
More info
Quiet bunch in here. Must be chocolate egg based!
Got the actual fault code today - C1A34. This was a useful exercise as I scanned the car with a Snapon Solus to compare with what my RSW software was getting, just to check if there were multiple suspension codes. The Solus does a few more things like a full read of the body computer, but generally all the same. Also suggested my EGR valves are getting sticky!!
C1A34 appears to be only triggered by a valve failure or wiring failure to the valve block. I tracked down the correct diagnostic sheet which I hope will be handy for others who are diagnosing and solving themselves. I will load to the appropriate gallery.
The suspension system does seem to be very very simple mechanically, and very logical electronically, so as long as problems are spotted early, all this stuff about replacing compressors seems to be the high cost end of the solution.
All I am missing is a knowledge of where the harnesses run under the car and therefore where the issue might lie, but in the absence of anything else, that is tomorrows job, after easter eggs of course!! I will post some photos in case they are helpful.
The workshop manual is there in various forms, as are the electrical wiring diagrams.
Too late to take a look myself, but if I’ve seen you haven’t found it tomorrow will have a look
Good luck, not that will necessarily help much
31st Mar 2018 10:51 pm
Globetrotter448
Member Since: 21 Mar 2017
Location: Londonderry NSW
Posts: 1780
did you have any height sensors replaced, if so, possible calibration required
1st Apr 2018 8:42 am
The_Wombat
Member Since: 03 Mar 2018
Location: Deepest darkest Cambridgeshire
Posts: 11
No, no height sensors replaced.
Based on the documentation, a height sensor replacement would not throw up the code C1A34, which relates to the right rear corner air valve.
These are the possible errors for this code:
- Right-hand rear corner valve, general electrical failure
- Rear valve block disconnected
- Rear valve block harness wiring short circuit to ground or high resistance
- Right-hand rear corner valve failure
- Air suspension control module failure
I am investigating item 3 as it seems the most reasonable at this stage. I do worry that something else might trigger the fault, but logically, the only way the system can tell you something about the corner valves is if there is an electrical signalling issue with them, so per the bullets above, either a module failure (unlikely), a valve failure (new block installed), or a harness/connector issue (most likely). The issue with harness and connectors is locating, finding, and testing them. Who knows in this mobile bungalow where the harness goes.
Documentation suggests 3 connectors:
- harness to valve block
- Short harness to main body harness under the boot floor
- Body harness to EAS module
That seems pretty straight forward so as soon as I have had some nice Easter croissants and coffee, I will be out there.
As Paul said in the immortal Simon Pegg film of the same name 'It's probin time'2000 Discovery 2 TD5
2004 Discovery 3 TDV6
1992 Alfa 75 V6 Cloverleaf
1992 Alfa 155 Q4
2001 Alfa GTV 24v
2003 Alfa 156 GTA SW
1997 Fiat Coupe 20VT
1st Apr 2018 9:23 am
The_Wombat
Member Since: 03 Mar 2018
Location: Deepest darkest Cambridgeshire
Posts: 11
Probin time
Well, probin time was fun! Quite easy as it happens.
Continuity probe into either the orange/black or purple/black wires from the valve block harness plug, and other probe into the back of the large white 20 pin harness connector, same colour wires, that is attached to the harness that exits the body after the rear wheel arch on the NS.
Orange/black and purple/black are the colours for the RH rear air valve signal wires. Bit fiddly and need to drop down the spare wheel and sit under the boot floor to access the 20 pin connector.
Orange/black fine, purple/black nothing. I stripped the harness back as far as I could reach (it disappears in front of the parking brake actuator and everything gets in the way from there) and couldn't see anything obvious, so cut the purple/black wire by the valve block plug and 6 inches from the 20 pin connector, fed new wire through the harness route, and soldered it in.
All working fine now. I am guessing either wire corrosion or rubbed through a little further up in the harness.
No photos as it was a bit dull, but realising that the air suspension system is very very straight forward, either:
- No air supply
- Leaking
- No power supply to various components
The error codes can only rely on performance of the pump (temp/pressure), and the electrical signals to the components, so are there no mysteries left in this life!!!2000 Discovery 2 TD5
2004 Discovery 3 TDV6
1992 Alfa 75 V6 Cloverleaf
1992 Alfa 155 Q4
2001 Alfa GTV 24v
2003 Alfa 156 GTA SW
1997 Fiat Coupe 20VT
1st Apr 2018 4:20 pm
biztechrx
Member Since: 22 Sep 2018
Location: Hershey, PA
Posts: 56
Same Error: C1A34
Both my wires are good.
Looks like it's time for a new Valve Block?
2008 Land Rover LR3 SE 4.4L
2010 Jaguar XF 4.2L
2019 No Boundaries 16.5 Off Road Trailer (Caravan)
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