Hi folks

Has anyone experienced an L405 body twitching? Feels like the car lifts up and then down a couple of cms on one corner. It's too fast to be the air suspension, must be the ACE system.


I scanned the car and found this fault - c1049-63 front axle rod pressure regulating valve

Is this a symptom of the valve block? It's a 2013 car, probably still got the original installed. Anyone changed one.....how hard is it? If necessary, I'll get a used later version from a breakers and replace it.

As always, thoughts and experiences much appreciated.

I don't see a C1049-63 error code in the manual, only these 2:

C1049-62 Front Axle Rod Pressure Regulating Valve - Signal compare failure
C1049-64 Front Axle Rod Pressure Regulating Valve – Signal plausibility failure

Which in a little more detail:

C1049-62 Front Axle Rod Pressure Regulating Valve - Signal compare failure

- Dynamic response hydraulic fluid circuit requires bleeding
- Dynamic response hydraulic fluid low
- Dynamic response hydraulic fluid leak from high front axle rod pressure primary circuit, secondary circuit or dynamic response hydraulic fluid reservoir
- Dynamic response hydraulic fluid contaminated Broken stabilisation link
- Broken roll bar module
- Sensor fault
- Valve fault - Sticking valve
- Actuator fault
- Dynamic response hydraulic fluid reservoir suction port screen damaged

Thank you fisha

I have fluid in the reservoir and there are no leaks. I will certainly follow your advice and look at the block and connections.

The car only seems to twitch when it's cold, after driving for 10 mins or so it stops. I wonder if the oil temperature has something to do with it.....could well point to a filter somewhere.....

Will keep you posted

The fluid tank is viewed as a serviceable item because of its filter … can’t remember the mileage to change it at though. 80k miles rings a bell. V8 or else ...

An update regarding the active roll issue.

Having read lots and lots of threads, it seems uncommanded body roll is not that uncommon. People have mentioned replacing various components but ultimately it seems like it's a valve block issue.

My car (2013) has the original CPLA type block fitted, it has not been replaced by the FLPA type.

I ran some diagnostics using GAP, trying to see what was moving and why, was it commanded electronically (ie, control module fault) or is it the valve block actuating on its own. Picture attached shows the Front Actuator Piston Regulator Valve jumping around, there is no electrical signal making this request.

So, in summary, I think I'm going to replace the CPLA block with a FPLA one, I'll pick one up off eBay.

The questions

Looking at the graph, has anyone seen this before? Does my thinking sound reasonable?

Has anyone replaced CPLA with FLPA, any issues?

The dreaded bleeding question, how do I bleed it afterwards without the special tool?

Many thanks for your thoughts

Now the graph

I’ve personally not had much experience with valve blocks at all luckily. However when my first 405 was quite young there was a TSB re changing the valve blocks. This was an end result after changing most other hardware after complaints of knocking suspension. Can you confirm whether yours was ever changed?
I presume yours is an early car?
I believe the replacement valve blocks came with multiple valves instead of just a single valve…

Hope this helps?

Hello

Yes, I am aware of the recall, I don't think mine was done. It's a 2013 car and fitted with the CPLA valve.

Thanks

Have you asked if the TSB is still live? I guess it will be… Then they can do the job for you FOC…

Hi all

To close off this post.

I replaced the valve block with the later FPLA type, as per the technical bulletin. I didn't need to bleed it post fit.

The car is fixed. No body twitching, no amber roll warnings, no issues.

Took a couple of hours, fairly easy job.

Regards