RRSPORT.CO.UK

    Forum   Gallery   Shop   Sponsors
Home > Faults & Fixes > Suspension Fault Tracing Help Needed
Post Reply  Down to end
Page 1 of 1
 
JS3



Member Since: 26 Nov 2013
Location: Yorkshire
Posts: 24

United Kingdom 2008 Range Rover Sport TDV8 HSE Buckingham Blue
Suspension Fault Tracing Help Needed

Hi all - I have the standard yellow suspension warning, 'Normal Ride Height Only' with fault code C1A20. Not the first time and previously used a repair kit for the original Hitachi compressor which improved things but still gave the same fault in off road height.

Ive repaired the compressor again (including end cap, filter beads, filters, o-rings, piston ring etc etc), although the motor gets VERY hot very quickly and slows down as the pressure increases - never had an overheating error though. I am trying to trace the fault to either a leak somewhere in the system or simply a broken compressor.

Firstly, when I log the compressor's activity using a diagnostic machine the compressor reaches pressures up to 200 psi within a few minutes - suggests the compressor is working well. But what should the operating pressure be? When in normal height Ive had it at either 14 psi or 45 psi. How long should the compressor run for?

Secondly, to try and trace an air leak in the system does anybody have an air line diagram? Including the non-return valves etc?

Thirdly, the 'gallery' I assume is the manifold block that controls each corner which is located at the front - but where exactly?

Thanks for the help.

Post #511564 Sun Dec 04 2016 9:53pm
View user's profile Send private message View poster's gallery Reply with quote
Paddi



Member Since: 06 Jul 2012
Location: Hertfordshire
Posts: 1563

United Kingdom 2008 Range Rover Sport TDV8 HSE Java Black

There isn't much in the workshop manual about pressure but there is this;

"The valve block also contains a pressure sensor which can be used to measure the system air pressure in the air springs and the
reservoir. The pressure sensor is connected via a harness connector to the air suspension control module. The control module
provides a 5V reference voltage to the pressure sensor and monitors the return signal voltage from the sensor.
Using this sensor, the control module controls the air supply unit operation and therefore limits the nominal system operating
pressure to 244 lbf/in2 (16.8 bar gage)."

EDIT: there is also this:

Exhaust Valve
The exhaust valve has three functions. It operates in conjunction with the pilot exhaust valve to allow air to be exhausted from the
air springs and/or the reservoir as described previously.
The valve also protects the system from over-pressure. The valve is connected into the main pressure gallery which is always subject
to the system pressure available in either the air springs or the reservoir. The valve is controlled by a spring which restricts the
maximum operating pressure to between 319 to 391 lbf/in2 (22.0 to 27 bar gage).
The minimum pressure in the system is also controlled by the exhaust valve to ensure that, even when deflated, the air springs
contain a positive pressure of approximately 14.5 lbf/in2 (1 bar gage) with respect to atmosphere. This protects the air spring by
ensuring it can still 'roll' over the piston without creasing.

(Note the 'air supply unit' is what Land Rover call whole unit including the compressor in this document)

There is a diagram of the 'air harness':

Click image to enlarge


The manual describes where the valve blocks are (as unhelpfully as possible):

The front valve block is attached to the right hand end of the front bumper armature assembly. The valve block has three attachment
lugs which are fitted with isolation rubber mounts. The rubber mounts locate in slots in the armature. The valve lugs locate in the
holes above the slots and are pushed downwards into positive location in the slots.

The rear valve block is located on the forward face of the left hand rear suspension turret. The valve block has three attachment lugs
which are fitted with isolation rubber mounts which locate in a bracket with three slotted holes. The bracket is attached to the left
hand side of the chassis. The isolation rubber mounts locate in the 'V' shaped slots and are pushed downwards into positive location
in the slots.

The reservoir valve block is attached to a bracket on the outside of the left hand chassis rail, between the reservoir and the air supply
unit. The valve block is located within the air supply unit acoustic box to protect it from dirt ingress and damage from stones. The
valve block has three attachment lugs which are fitted with isolation rubber mounts. The rubber mounts locate in the chassis bracket
which has three corresponding 'V' shaped slots. the rubber mounts are pushed downwards into positive location in the slots.

Did you mean fault code CIA2064?
Pressure increase too slow when filling reservoir

Possible causes:
Reservoir valve stuck closed
Reservoir pipe blocked/damaged
Reservoir port blocked/restricted
Pressure sensor fault

Hope that is some help. I'm sure other will chime in with some more practical advice. 2008 MY Java Black TDV8 HSE

Post #511605 Mon Dec 05 2016 6:14pm
View user's profile Send private message View poster's gallery Reply with quote
JS3



Member Since: 26 Nov 2013
Location: Yorkshire
Posts: 24

United Kingdom 2008 Range Rover Sport TDV8 HSE Buckingham Blue

Thanks Paddi - thats a great help.

The diagnostic code doesnt have '64' at the end but has the 'Pressure increase too slow when filling reservoir' description.

I spent some brief time today looking at the diagnostic machine read out and concur with the workshop manual. 14.5 psi residual pressure, 246 psi 'operating' pressure, and the pressure sensor reference voltage. Although the operating pressure was at 246 psi, the sensor voltage increased slowly from 3.2v to 3.6v over the first minute or so the compressor was active. The compressor then slows to a stop, then the amber light appears and compressor is stopped.

I believe the reservoir valve is open, but needs to be confirmed. Any other thoughts? Is the pressure sensor operating correctly? Or should this be at 5v when at 246 psi?

Thanks again.

Post #511613 Mon Dec 05 2016 9:41pm
View user's profile Send private message View poster's gallery Reply with quote
Disco_Mikey



Member Since: 08 Apr 2012
Location: Dundee, Scotland
Posts: 4321

United Kingdom 2010 Range Rover Sport Supercharged HSE Santorini Black
Re: Suspension Fault Tracing Help Needed

JS3 wrote:
Hi all - I have the standard yellow suspension warning, 'Normal Ride Height Only' with fault code C1A20. Not the first time and previously used a repair kit for the original Hitachi compressor which improved things but still gave the same fault in off road height.

Ive repaired the compressor again (including end cap, filter beads, filters, o-rings, piston ring etc etc), although the motor gets VERY hot very quickly and slows down as the pressure increases - never had an overheating error though. I am trying to trace the fault to either a leak somewhere in the system or simply a broken compressor


This suggests to me that the compressor is shafted

A healthy Hitachi/Dunlop compressor should be able to raise the car from access height to normal, and refill an empt air tank to 18 bar without cutting off at 130degrees, just!

A healthy AMK will also do the same, but temperatures will be much lower

Post #511614 Mon Dec 05 2016 9:48pm
View user's profile Send private message View poster's gallery Reply with quote
JS3



Member Since: 26 Nov 2013
Location: Yorkshire
Posts: 24

United Kingdom 2008 Range Rover Sport TDV8 HSE Buckingham Blue

Thanks Mikey. Even though I repaired the compressor?

The compressor seems to be running longer than it should and the temperature reaches 180 degF within a minute. How long should the compressor run for? And if the pressure is at 246 psi, why does the compressor continue to run?

Post #511615 Mon Dec 05 2016 9:59pm
View user's profile Send private message View poster's gallery Reply with quote
Disco_Mikey



Member Since: 08 Apr 2012
Location: Dundee, Scotland
Posts: 4321

United Kingdom 2010 Range Rover Sport Supercharged HSE Santorini Black

If the compressor gets hot in a short space of time, its generally a faulty compressor.
An air leak would decrease load on the compressor, and take longer to heat up, but would run longer to generate pressure

By my calculations, working pressure is 1780kPa, or 17.8bar, or 261(ish)psi Thumbs Up

Post #511620 Mon Dec 05 2016 10:36pm
View user's profile Send private message View poster's gallery Reply with quote
JS3



Member Since: 26 Nov 2013
Location: Yorkshire
Posts: 24

United Kingdom 2008 Range Rover Sport TDV8 HSE Buckingham Blue

Thanks Mikey - when I say heating up, it is the motor unit of the compressor that gets very hot.

Would you investigate the pressure sensor any further? I have around 3.6v at 264 psi. I just want to make sure I fully investigate all avenues before I spend £350 on a new compressor.

Again, thanks for the help.

Post #511656 Tue Dec 06 2016 2:11pm
View user's profile Send private message View poster's gallery Reply with quote
JS3



Member Since: 26 Nov 2013
Location: Yorkshire
Posts: 24

United Kingdom 2008 Range Rover Sport TDV8 HSE Buckingham Blue

Thanks for the help guys. I have done some investigating into this fault and could not definitively identify a fault within the air system (thanks to Paddi's list) so opted for a new compressor (last item on the list).

New compressor fitted and no more fault codes. However, the compressor still runs for what seems a long period, around 90 seconds to 2 mins. The struts are inflated within a few seconds when changing height, but the remaining time seems to be spent pressuring the reservoir. There appear to be no major leaks on the reservoir.

Is this time normal? I thought I had read somewhere it should only take 20-30 seconds but could be mistaken.

Post #512509 Sat Dec 17 2016 7:51pm
View user's profile Send private message View poster's gallery Reply with quote
phillh



Member Since: 09 Oct 2016
Location: Hertfordshire
Posts: 198

United Kingdom 2005 Range Rover Sport TDV6 HSE Zermatt Silver

My son had issues with the pump on his L322 (full fat RR). Its different to the RRS, under the spare wheel in the boot, but the systems are generally pretty similar.

He bought a repair kit, replaced seals, piston etc and it improved a bit but still took ages to lift the car.

In the end he bought a new pump and it has been fine ever since.

Post #512516 Sat Dec 17 2016 8:54pm
View user's profile Send private message View poster's gallery Post Reply
Post Reply  Back to top
Page 1 of 1
All times are GMT

Jump to  
Previous Topic | Next Topic >
Posting Rules
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Site Copyright © 2005-2024 Futuranet Ltd & Martin Lewis
RRSPORT.CO.UK RSS Feed - All Forums

Switch to Mobile site