2006 Citroen C4 Auto | AL4 slipping in 1st gear eventually engages with a clunk, when warm

pug88

New member
Hi all,

I recently picked up a 2006 Citroen C4 Auto, the car drives fine until after some period of driving (say 30-45 minutes) the car will begin to lose the ability to "creep" forward from a stationary position, i.e. If the car is stopped on a flat road, letting go of the foot brake will result in no forward motion (creep forward). If I give it some throttle, the RPM will rise (higher than usually required) and it will eventually bite/bump/clunk and drive off. If I repeat this process multiple times it will eventually become nearly impossible to get the car moving in 1st (will needs lots of RPM to get the bite), the only way to get the car moving is going to "Manual" mode and putting the car into 2nd gear.

Does anyone know what my next steps are to troubleshoot this.

Regards,
J.
 

dimistyle

Well-known member
If its never had the oil replaced and never had the solenoids replaced you probably have a low chance to recover its workings and will need to be rebuilt....not cheap.
Plenty of horror stories on AF.

More than likely clutches or brake bands are too far worn to work or internal pressure is too low.

Get the code off the side of the AL4 behind plastic wheel guard covers on the circular face and see if you can find a second hand unit to swap out.

An oil change may keep it going for a few more months until a permanent solution is found.

I only had 3rd and 4th gear on manual mode for 6 months before no more movement and box swap had to be done.
 

seasink

1000+ Posts
Diagbox is the later application, from about when your car was made, and includes Lexia. It only runs on Windows and is a pig to install, Get good instructions. Do not let it go online.
 

Ken W

1000+ Posts
Diagbox is not such a pig to install if you have the capacity on your PC to use VMware to run a pre-installed version of Diagbox installed on a windows XP SP3 partition. This setup allows you to even run Diagbox on a Windows 10 64 bit install. Start a conversation with Blufires if you want instructions and download information. Remember to disconnect your computer from any networks when you run the Diagbox Partition this system too.

Cheers, Ken
 

pug88

New member
Thanks all, shouldn't be too much of an issue. I've already got a Virtual Machine running with the full Workshop manual Software for the C4. It should be fairly easy to spin up a WinXP SP3 VM.

I ended up getting: https://ebay.us/xzF8fG
 

Ken W

1000+ Posts
Blufires VM loads up the Win XP with the diagbox ready to run with a double click from the win xp desktop. It even remembers screen resizes so you can see the whole diagbox screen.

Cheers, Ken
 

ozVTR

Member
Hi all,

I recently picked up a 2006 Citroen C4 Auto, the car drives fine until after some period of driving (say 30-45 minutes) the car will begin to lose the ability to "creep" forward from a stationary position, i.e. If the car is stopped on a flat road, letting go of the foot brake will result in no forward motion (creep forward). If I give it some throttle, the RPM will rise (higher than usually required) and it will eventually bite/bump/clunk and drive off. If I repeat this process multiple times it will eventually become nearly impossible to get the car moving in 1st (will needs lots of RPM to get the bite), the only way to get the car moving is going to "Manual" mode and putting the car into 2nd gear.

Does anyone know what my next steps are to troubleshoot this.

Regards,
J.
I would drain at least some of the fluid and inspect it.
If its red it's been changed at least once. If it's clear red, it's been changed recently. Most likely this is the wrong fluid (but there are some brands that are red and do, apparently, work E.g. Penrite's fully synthetic).
If it's clear amber then the correct fluid has just been added. You would be wasting your time changing the fluid, it hasn't worked!
If its grey it probably has never been changed.
I personally use Penrite BMV, as it appears to be the same as Mobil LT71141, The fluid recommended by the gearbox manufacturer. Again my preference, others are free to disagree. Also, Nulon appears to do a fluid conforming to the Mobil spec (SYNATF). I am sure you will be inundated with fluid recommendations. You will need to make up your own mind.
You can try replacing the primary and converter pressure regulator electro valves. You have nothing to loose. The only problem with that is that the Chinese knock off valves can be faulty "out-of-the-box". Putting you right back where you started. I would buy more than 2 to give yourself a fighting chance :p. On average, "genuine" valves on Ebay start at about $70 each.
Lexia will tell you the temperature of the transmission fluid. You said the transmission fails "after some period". Running temps seem to between 60-80'C. If the heat exchanger is not working, the transmission fluid could get hot and break down. Blockages in the heat exchanger are common if the engine coolant is dirty.

Did you get three beeps and the 'S' and '*' flashing on the dash? Or a warning on the center display?
 

pug88

New member
Thanks for the reply @ozVTR

Did you get three beeps and the 'S' and '*' flashing on the dash? Or a warning on the center display?

Currently not seeing any error codes or warning logs. I ordered the Lexia 3 last weekend but I'm still waiting for it to arrive in the post (Apparently an Australian eBay'er but I doubt it now). We proceeded to change the oil 3 times (Using the Penrite Synthentic ATF) with a 30 minute drive between each change. The Penrite is a deep Red new out of the bottle, after the 3rd change it's still got a brown look to it but it's hard to tell because it's definately thicker/darker than normal ATF.

The issue still occurs at about the 35-45 minute mark of driving, the car will begin to exhibit the following symptoms:
  • Driving the car normally for 35-45 minutes (not spirited/hard)
  • At approximatly the 45 min mark of driving there are no issues in 2nd, 3rd & 4th gear (smooth, changes without issue and no clunks)
  • When the car comes to a stop (say at a traffic light/intersecition) the car drops to 1st gear (as normal), at this point the car has no forward drive if I release my foot from the brake pedal it will either not move, or roll backwards on a slight incline (this doesn't occur 100% of the time, maybe every second or third time)
    • During this situation, sometimes there will be a light "clunk" while I have my foot on the break pedal (after about 5-20 seconds, after dropping to 1st) and the car will regain forward drive
    • Otherwise the car will free rev, until a slighly harder clunk results in the car regaining momentum again
It's definately a 1st gear issue, if I turn the car into "SNOW" mode, the car will avoid using 1st gear and the car drives off in 2nd gear without issue.

Things to check with the Lexia 3:
  • Oil Temp (Before/During) the issue
  • Check pressure measured by the Transmission pressure sensor (Before/After)
  • Hopefully perform some relay tests (before & after the issue occurs)
 

RINGER

Well-known member
Thanks for the reply @ozVTR



Currently not seeing any error codes or warning logs. I ordered the Lexia 3 last weekend but I'm still waiting for it to arrive in the post (Apparently an Australian eBay'er but I doubt it now). We proceeded to change the oil 3 times (Using the Penrite Synthentic ATF) with a 30 minute drive between each change. The Penrite is a deep Red new out of the bottle, after the 3rd change it's still got a brown look to it but it's hard to tell because it's definately thicker/darker than normal ATF.

The issue still occurs at about the 35-45 minute mark of driving, the car will begin to exhibit the following symptoms:
  • Driving the car normally for 35-45 minutes (not spirited/hard)
  • At approximatly the 45 min mark of driving there are no issues in 2nd, 3rd & 4th gear (smooth, changes without issue and no clunks)
  • When the car comes to a stop (say at a traffic light/intersecition) the car drops to 1st gear (as normal), at this point the car has no forward drive if I release my foot from the brake pedal it will either not move, or roll backwards on a slight incline (this doesn't occur 100% of the time, maybe every second or third time)
    • During this situation, sometimes there will be a light "clunk" while I have my foot on the break pedal (after about 5-20 seconds, after dropping to 1st) and the car will regain forward drive
    • Otherwise the car will free rev, until a slighly harder clunk results in the car regaining momentum again
It's definately a 1st gear issue, if I turn the car into "SNOW" mode, the car will avoid using 1st gear and the car drives off in 2nd gear without issue.

Things to check with the Lexia 3:
  • Oil Temp (Before/During) the issue
  • Check pressure measured by the Transmission pressure sensor (Before/After)
  • Hopefully perform some relay tests (before & after the issue occurs)
Definitely
 

dimistyle

Well-known member
Not sounding like a positive change after the new oil was filled.
If you drive it in manual mode I believe you will lose 1st a lot earlier so either the brake band has worn or valve body is worn and cannot keep the pressure on the the band. Snow usually starts in 3rd but can be used to keep you going in a forward direction.

As you say the car will roll backwards so no pressure holding the brake band on in 1st gear.

I have a known good VB and some extra solenoids but if your thinking of opening the front of the auto be prepared with correct tools and dust free conditions as its a pretty messy frustrating job.
 

pug88

New member
Snow usually starts in 3rd but can be used to keep you going in a forward direction.

With testing today, I found that with using SNOW mode, the car will start from a dead stop in 2nd gear perfectly fine, which I believe is just reducing torque by using a higher gear. I'd imagine this wouldn't be great for really steep hills, but for the most part the car is quite happy getting away in 2nd gear.

Going off this diagram below, the only non-common element between all the engaged equipment in 1st gear is EVS3, so just for a little bit of fun I'm going to replace the EVS3 + EVS4 electrovalves if everything on the Lexia 3 checks out with the above mentioned tests. As I'm not seeing any issues with gears 2, 3 & 4, it would seem there must be some non-common element or condition that's causing this. As it appears replacing those two electrovalves are fairly easy (don't have to remove the entire valve body), it's possibly a quick sanity check to just see if maybe one of solenoids has died. I only really need to replace #3, but I'll replace #3 + #4 because I'm in there anyway and the donor valves I have are known to not have had any issues with 1st gear.

I guess it's all a slow process to eliminating the easier options and getting to the point where we can say it's definately something more serious. But it would be really awesome if it's something as simple as a single $20 valve. :spy:

2021-06-12_222911.png

Will report back with how I go.

Regards,
Jason.
 

pug88

New member
I have a known good VB and some extra solenoids but if your thinking of opening the front of the auto be prepared with correct tools and dust free conditions as its a pretty messy frustrating job.

What's a VB? 🍺

How much were you after for a few of those electrovalves, are they also know good like the VB?
 

T03Y

Member
Hi J,
Just reading your thread I’m reminded of my AL4 troubles and when I first found this forum. It’s 6 years ago now and 11 pages long, but you might find something of interest-
https://www.aussiefrogs.com/forum/index.php?threads/03-citroen-c5-2-0-hdi-auto-help.115034/

The folks here were a godsend and I eventually got myself out of trouble when one of them offered to help out. In short, I bought a clutch kit from alibaba and a retired Citroen mechanic installed it via access in the front left wheel well.

the other commenters on your post are far more knowledgeable than I but I haven’t heard of anyone else using this solution.

One Mercedes and one Peugeot later, I am again the owner of a C5 (‘06), again I’m sorting out small issues but not with the gearbox thankfully. Good luck with yours I’m happy to help if I can.
 

dimistyle

Well-known member
What's a VB? 🍺

How much were you after for a few of those electrovalves, are they also know good like the VB?
Let me check what's in the boxes. I should have some of the smaller EVs to swap 3 and 4.
You will also need to unplug the wiring harness from the VB and put on a clean bench to replace the suspect EVs.

Don't open it but you can wash it down in diesel as there's also a little filter inside VB which can get blocked but not sure what affect this has.

PM me as a reminder to get into the AL4 spares.
 
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