Suspension fault

In Follow up to my post last week concerning my 2008 vogue suspension fault ive finally had a moment to connect my solus machine, the codes are as follows
C1B18: supply voltage x ref check
C1A20: pressure increases too slowly when filling reservoir
U0416: Invalid data received from vehicle dynamics control mudule
U0401: Invalid date received from ECM/PCM

I cleared all the codes and started the vehicle again and got the C1A20 code again, i looked at live data also and noticed the rear right ride height sensor operating voltage was only 1.98 volts compared to the rest that were all above 3 volts, but i cant understand if a faulty ride height sensor would cause a slow reservoir pressure build up? your help here would be greatly appreciated Thanks in advance

Knackered Pump....

Saint.V8 said:

Knackered Pump....

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i thought that so i took the cover off the compressor and ran it while i checked the air flow, there seems to be plenty of out put from the compressor, theres 1 8mm pipe from the compressor head that feeds 2 cylinders at either side of the compressor then at the other side there is a plastic cylinder with 2 smaller pipes running from it 1 with a blue ended fitting and 1 with a orange ended fitting theres plenty of pressure from all 3 pipes from what i can judge just by holding my finger over the pipe ends, it blows my finger off very quicklym is there any other reason for it to build pressire in the reservoir slowly/ dont want to buy a compressor then realise its something else

Not always, just had same fault on my LR3 with same fault codes, I know it is not the same vehicle but they share similarities and the compresseors are different I think. The LR 3 has a history of this so after fitting a compressor kit and dryer (available from LR) it still had the fault so more investigation revealed the next possibility was the pressure switch, relief valve or a blocked pipe due to desiccant from dryer, I found a used complete transfer relief valve on the bay, since fitting all has been well no faults and suspension operates as it should, save me nearly 300 quid! So before you throw a compressor at it make sure you do some thorough checks and if the compressor is making good pressure then you need to look elsewhere.

right ive done a little exploring of the air system, the compressor output is fine i blew a tyre up with it using a modified pipe no problem, i stripped the valve located on rubber bungs at the rear of the compressor and was greated with a rusty watery mess which i cleaned out and reassembled, i then filled the air outlet pipe with wd 40 connected it back to the valve and ran the compressor to get it round the full air system in the hope of flushing it out a little, i then started the car and all seemed fine albeit i got a vehicle rising slowly message on the dash but no error codes stored, which is better than before when it would just shut down altigether. The car ran great for 10 mins then the reservoir underneath seemed to overpressure and released its air causing the same fault as original ie suspension fault normal height only, i restarted the vehicle and again all ok so im gonna let the wd40 work its way into the valves and hopefully remove any crud in them, any one else care to comment??

Check the battery voltage.

I am sure there is some sort of valve incorporated in the tee piece in blue pipe just upside the compressor that has caused problem from what I can remember from previous posts by someone on here, maybe worth checking?

Battery voltage is fine 13.7 volts at idle, the t piece you mentioned i think is incorporated into the valve at the rear of the compressor which i have cleaned out already and now clicks when operated and switches as it should i think the problem lies further in the air system but im not sure where the rest of the valves are ie the distribution valve for the various air springs and the pressure relief valve for the reservoir also i have never heard the reservoir vent like it does now its very loud when it happens

It's not the flow you need it's the pressure.A typical tyre may take 28 psi and feel rock hard, your pump should run in the region of 160 psi +. This can be checked with pressure gauge and a couple of airline push fittings. A handy tool to have in any range rover toolbox.

rewmer said:

It's not the flow you need it's the pressure.A typical tyre may take 28 psi and feel rock hard, your pump should run in the region of 160 psi +. This can be checked with pressure gauge and a couple of airline push fittings. A handy tool to have in any range rover toolbox.

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cheers i checked reservoir pressure earlier with the solus it was reading 168kpa, not sure what that equates to in psi ?? assuming the pressure valve on the reservoir is reading correctly

Two things;
Your compressor is worn out.
Do not introduce a lubricant such as WD40 - it is a dry air system.....

That's about 24 psi you've got there. Pumps pooped.

Look for a thread by a member called RS2000CUSTOM - can't remember the exact tile but went along the lines of 'Reservoir Static When Filling' he found out it was his valve block getting stuck or similar...might be worth a read.

Plagiarising parrot

Hi all thanks for all the info/help i finally found the problem, the main charge pipe to the reservoir had blown out of the union at the reservoir which would explain the loud hiss every time i opened the drivers door as it switched the suspension off thus exhausting through the pipe, i refitted the pipe with a new union, still cant fathom out how the suspension still raised albeit slowly with the main feed pipe not attached, must have a switching valve somewhere to divert pressure through the other two blue pipes leading from the compressor, and the air springs use a combination of reservoir and compressor air to quickly inflate the airsprings. Any ways just goes to show that a little digging around first can save a lot of money rather than jumping in and buying a new compressor for no reason at all other than someone told you to. BTW the compressor reservoir now stores pressure to 989kpa, which i checked with range rover and that is normal operating pressure so all is well again.

Good find - but how were we supposed to know the pipe had come a drift????

I guess when someone posts, we (rightly or wrongly) assume the post-er would check all connections and electrical supplies including fuses etc before they then post on their issue.

Still I am glad you have found your issue and it worked out a cheap fix - gotta love them ones!!

i did say in the earlier posts that i could hear air escaping when i opened the drivers door but because the pipes are under the fuel tank skid plate you have to have the vehicle on a ramp and remove the covers to see the pipes but most people dont have access to a vehicle lift, i had to call a few favours in to borrow one, nice cheap fix thoughm as you say