Hi guys

I’m new here, I done some reading but can’t quite nail down my problem or where to start so thought I’d post up

My rrs 06 has the typical suspension fault. It’s currently stuck in access mode so it’s as bumpy as hell. I can’t change anything

I’m assuming it will end up being a compressor as I’ve read these are notorious but I just bought myself a code reader and some of the fault codes give me hope it could be electrical?
The codes I’m getting are u0421, u0132, c1a27 which all relate to the circuit. It did have a historic c1a20 which related to the compressor but I cleared this and it didn’t return. All the other 3 were cleared but returned immediately

So I checked the 3 suspension fuses and they were ok. What would you recommend I look at next? Wiring? Relay?

A few months back I did have a suspension light on my dash that would come on intermittently but everything worked fine still. At the time I was told that could have been a sensor.

If anyone could offer some advice it would really be appreciated
Thanks

u codes are lost comms and can be ignores normally but check wireing connecters where they rub under arches and the like search on here and sister site disco 3 there are a few thread's about wires chaffing in and around the wheel arch

Thanks. I’ll take a look under the car tomorrow.

Could it be on any of the 4 wheel arches or is there one particular arch I should look? Do I need to remove plastic covers?

Cheers

i have heard of problems front nearside and offside rear try the rear first as there's no cover there but someone will come along with more idea's and knowledge

Cheers. Yeah hopefully someone will give me some pointers who’s had the same problem. I done a search but couldn’t find anything relevant.

Does anyone know if it could be the relay? Is this a common failure?

Anyone? Some help would really be appreciated

Thanks

The problem is that the codes are incomplete. Presumably a generic reader was used. There are three entries for C1A27, 3 entries for U0132. By the way, you can download a free copy of the workshop manual which is invaluable. Search for a member on here called naks. There a link in his signature block to a download.

From the workshop manual following a quick search:

C1A27-12 Compressor
Circuit

Compressor voltage
present when compressor
not requested

Air compressor harness
wiring short circuit to
power

Air compressor relay fault

Air suspension control
module failure

Refer to the guided diagnostic routine for this code on the
approved diagnostic system. Refer to the warranty policy and
procedures manual if a module is suspect.

C1A27-14 Compressor
Circuit
Compressor voltage
present when compressor
requested

Air suspension control
module supply (COMP_V)
fuse in battery junction
box (BJB) failed

Air supply relay/air
compresor supply fusible
link in BJB failed/not
installed

Air compressor harness
wiring short circuit to
ground or high resistance

Air compressor relay
failure

Air suspension control
module failure

Check/renew fuses as necessary. Refer to the electircal guides.
Refer to the guided diagnostic routine for this code on the
approved diagnostic system. Refer to the warranty policy and
procedures manual if a module is suspect.


C1A27-29 Compressor
Circuit
Compressor relay control
voltage signal invalid

Air compressor harness
wiring short circuit to
power

Air compressor relay fault

Air suspension control
module failure

DTC C1A2712 will be set first. Refer to the guided diagnostic
routine for this code on the approved diagnostic system. Refer to
the warranty policy and procedures manual if a module is
suspect.

U0132-87 Lost
communication
with suspension
control module ‘A’
- missing message

The terrain response
control module has not
received one or more
expected messages from
the air suspension control
module

High speed CAN circuit
communications failure

Open circuit air
suspension control
module, power feed

Open circuit air
suspension control
module, ground supply

Air suspension control
module disconnected
from the high speed CAN
communication bus

Open circuit air
suspension control
module high speed CAN
low circuit

Open circuit air
suspension control
module high speed CAN
high circuit

Air suspension control
module not configured

Air suspension control
module failure

Using the manufacturer approved diagnostic system, check the air
suspension control module for DTCs and refer to the relevant DTC
index. Using the manufacturer approved diagnostic system, carry
out network integrity test. Using the manufacturer approved
diagnostic system, re-configure the air suspension control
module. Refer to electrical circuit diagrams, check power feed and
ground supplies, to air suspension control module for open circuit.
Check for open circuit air suspension control module high speed
CAN low circuit. Check for open circuit air suspension control
module high speed CAN high circuit, repair as necessary. Suspect
the air suspension control module, check and install a new air
suspension control module as required, refer to the new
module/component installation note at the top of the DTC Index.
Check the system is operating correctly and the DTC does not return

U0132-87 Lost Communication
With Ride Level
Control Module -
Missing Message
Missing message from
the Air Suspension
Control Module

CAN Network fault

Check the Air Suspension Control Module for stored DTCs. Using
the manufacturer approved diagnostic system, complete the CAN
Network Integrity test. Refer to the electrical circuit diagrams and
check the CAN Network between the Adaptive Front Lighting
System (AFS) Control Module and the Air Suspension Control
Module

U0132-86 Lost Communication
With Suspension Control
Module "A" - Signal
invalid
Air suspension timed out,
signal out of range or
signal invalid

Refer to the electrical circuit diagrams and check the
power and ground connections to the module. Using
the manufacturer approved diagnostic system,
complete a CAN network integrity test. Refer to the
electrical circuit diagrams and check the CAN
network between the all suspension control module
and transfer box control module
Using the manufacturer approved diagnostic system
carry out the guided diagnostic routine

U0421-81 Invalid data received from
the air suspension control
module
Air suspension control module
fault

Check for CAN or module DTCs. Check the power
and ground circuits to the air suspension control
module, rectify as necessary. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Thanks for that. My scanner is The Icarsoft 930 for Land Rover. It’s under £100 so I guess you get what you pay for.

In your experience would hunting around the suspension for broken wires and replacing the relay be a good place to start with the info I do have? Or do I really need a better scan?

Cheers

If you remove the relay you can bridge the 2 large contacts and see if the Comp runs.
You may get a little spark.

Don’t run it for too long though.
May gives clues.

You can also power the compressor directly

Thanks Andy

I bridged the relay as you suggested and nothing happens. Not even a spark.

I guess that means my relay is probably ok and there’s no power coming in so could be a broken wire somewhere? What do you think? Should I run power to the compressor directly next or start looking for wire problems?

Cheers

May as well power compressor directly on the thick wires.

And or

If you have a test light monitor the wires at the back and bridge the relay again and see if the light comes on.

There are connectors n the front passenger wheel arch (remove plastic)

Thanks Andy. I’ll try and get that tested tomorrow and report back.
I don’t have a test light monitor. So if I just hook up a positive and negative at the battery and put to the compressor directly? Are the connectors on the compressor obvious? I’ll use 2.5mm twin and earth cable

Is access to the compressor good? What do I need to remove to get to it?

Cheers

I just watched this vid.

I assume the compressor is same place on uk cars, rear passenger side?

Do I need to take rear n/s wheel off? They say to remove it but on the vid you can see the wheel is still on lol

Electrics look straight forward red and black wires

Cheers

Same place.

Yeah leave the wheel on. Though loosening the nuts before jacking keeps your options open.

Yeah thick red black wires from memory



Removal of the 2 thick pipes if the compressor is duff requires wheel removal

Don’t use the factory jack on these. They are very dangerous.