Another AL4/DPO electro-valve replacement guide.

If you have a Tip or Trick, some advice or you just want others to know something that is specific to the a Citroen C3 with an automatic gear-box , please, post it here. Includes the 4 speed AL4 with PRND and the 5 speed semi-automatic (SensoDrive) with '+ and -' controls.
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Think: Auto not changing up or down, snowflake and sport flashing, flappy paddles and sensodrive not changing gear.
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My Name: Ozvtr

Posts: 957
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
Has thanked: 37 times
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EDIT: This tutorial follows as close as practical the amalgam of texts, PDf's and assorted publications found scattered across the 'net on the AL4 gearbox. I say amalgam because no single piece of reference material (that I found) distinctly explained the steps required. Consequently, using practice, I have tried to interpret the intent of the manual in a practical way.
This is by no means the ONLY way to service the electrovalves and re-align the gear selector, but from my interpretation, this is the official way.

One (and there are many) of the reasons the AL4 automatic gearbox fails is because of the failure of either the torque converter lock up electro-valve or the main pressure modulating electro-valve. Again, this is not the only reason the gearbox fails! There can be damage to mechanical components and all sorts of other reasons. However if you do a bit of research on the 'net and you decide that these electro-valves are the fault in your gearbox, this is the way to service them.
It is best to replace them as a pair as it is difficult to detect which is causing your problem and if one fails the other may not be far behind!

There is an existing post on servicing the electro-valves by Jagpurr on this site.
Jagpurr's post is very good but seeing as things are very quiet at the moment I have decided to do an entirely new post.
I have added photos with clearer shots of the front of the gearbox and post-installation instructions for alignment of the selector switch and gear selector.
valve_change 001.jpg
valve_change 001.jpg (37.37 KiB) Viewed 561 times
The first thing I want to address is the "manual valve". To service the valve body you will need to deal with the manual valve. This valve is (basically) a cylindrical, steel valve connected between the selector quadrant (a device in the transmission, I'll get to it in a minute) and the valve body (the "hydraulic heart" of the transmission). Typically it falls out when you remove the valve body from the transmission. It is not retained by anything and can slide all the way through the valve body! So be careful with it. Just for your information, I'll tell you something about it and what it's for.
As you know, in most automatic transmissions the actual shifting of gears is done by a computer connected to electro-valves in the transmission. After all that's why this tutorial exists!? The electro-valves go bung? It's all "fly by wire" nowadays isn't it? But where is the fail safe? What if the computer goes psycho? What if it decides to go into reverse while you are driving along the highway? Well, that's where the manual valve comes in. Your selector stick in the cabin is physically connected the transmission via a Bowden cable and onto this manual valve. The valve directs hydraulic fluid to the forward speed circuit or reverse speed circuit or no where in the case of park and neutral.
So the driver always has fundamental control over the transmission.
Actually, there are a number of these rudimentary types of valves in the valve body, selecting gears and locking up bands. They are controlled by these electro-valves. Yes, valves controlling valves! But again, you can look this stuff on the 'net if you are interested.
Now on with the show!
valve_change 002.jpg
I would recommend disconnecting the battery before proceeding. You will need to perform a BSI reset before and after connecting the battery (search this site). But before doing all that, place the gear selector in the neutral position. Once the battery is removed the selector will be locked if it is left in park. Make sure the hand brake is on and the car can not roll away.
valve_change 003.jpg
The first thing you will need to do is remove the air filter box.
valve_change 005.jpg
You will (eventually) need to gain access to the oil filler port, the selector cable ball joint, Bowden cable retainer and the selector switch.
I will not be going through draining or refilling the auto box as that is a post all by itself and would over complicate this post (it's already complicated enough). However at this point there is no need to drain the box as we will be doing that in a minute (you'll see).
The next part involves removing the selector cable. If you feel confident that you can put everything back exactly the way it came, then you can skip removal of the cable. But read through all my instructions and see if you are still confident that you don't need to remove the cable. The cable can be removed at practically any time, it doesn't have to be done a this point. It can be done after the valve body has been serviced but I will go through the steps now.
valve_change 006.jpg
valve_change 007.jpg
Remove the ball joint connector from the ball joint on the selector switch arm. Press inward on the orange "ears" of the ball joint retainer. Pull upward on the blue rod end while pushing down and inwards on the orange ears.
valve_change 008.jpg
valve_change 08a.jpg
The Bowden cable retainer is held in place by a small clear tab. Pull the pin out while pulling the the retainer upwards off the bracket. The pin is spring loaded. You can now move the entire cable assembly out of your way.
valve_change 009.jpg
The best way to gain access to the valve body is to remove all the coolant hoses in front of the transmission.
The valve body will come out if you leave all the hoses in place. It's faster to leave them on, but not easier...if that makes any sense! You could remove the engine cooling fan assembly too. Again it all can be done with this stuff in the way but its a pain trying to work around them. The valve body that you will eventually remove is heavy, awkward slippery when covered in oil and for the most part you will be doing all of this on you back under the car. Again, I will not be going through draining the cooling system or removal of the radiator hoses. that is covered elsewhere on the site.

The transmission ECU.
The ECU sits on a (heavy steel) bracket on the front of the transmission and in front of the cover to the valve body. It needs to be removed.
valve_change 010.jpg
Remove the plastic ECU cover. Then remove the large connector from the top of the ECU. There are 3 cable tie fasteners on the ECU bracket and you need to release the cable from the bracket. I hate these things!! You typically destroy them removing them but the wiring loom needs to be separated from the bracket. You could just let the ECU bracket hang down but it gets in the way.
valve_change 011.jpg
valve_change 012.jpg
valve_change 013.jpg
ATTENTION:WARNING: there are 3 bolts holding the bracket and ECU onto the transmission.The 2 on the right hand side (as viewed from the front) have large threads and are not a problem. AS Jagpurr says you may need to deflect the brake lines out of the way. HOWEVER, the single bolt on the left hand side (on the front), oh boy!!! Make sure the two bolts on the right hand side are loose but not removed. VERY carefully unscrew the left hand bolt. The thread in the transmission housing is VERY delicate and can strip out. The bolt points slightly "upwards" so be careful removing and installing!! If you zoom in to the picture of the LH bolt you will see the thread has been damaged! I didn't do it AND this is NOT the first gearbox that I have had this problem on!!
EDIT: OZ from the future here. The bracket that holds the gearbox ECU puts pressure on the left hand bolt because the right hand bolts push the plate sideways. Undo the right hand bolts first. Screw them out until the bolt heads are clear of the bracket. Then undo the left hand bolt. Otherwise the sideways pressure of the bracket damages the threads of the left hand bolt. That then chews out the aluminium threads of the bolt hole. When putting the ECU bracket back, install all the bolts loosely, tighten up the left hand bolt first then tighten the right hand bolts.
valve_change 014.jpg
The valve body cover has 4 torx head bolts. Remove the bolts and the cover. Attention: if you have not drained the gear box of it's oil, about 2 litres of oil will come out by removing the valve body cover!!! So have a drain pan ready. I recommend draining the gearbox vie the drain plug in the bottom of the gearbox using a clean oil pan. Carefully drain the pan and inspect for metal fragments in the bottom of the pan. I will cover draining and filling the gearbox in another post.
NOTE; stuck to the INSIDE of the cover will be 2 bar magnets. They can be pulled off the cover for cleaning. If there is a lot of metal stuck to these magnets you may consider cleaning the valve body and particularly the plastic filter inside the secondary valve body. If there is a light film of metal (looks like a grey slurry), I wouldn't worry about cleaning. If they look like porcupines...and the gearbox performance is bad, there may be damage to the gearbox that replacing the valves might not fix!
valve_change 015.jpg
valve_change 016.jpg
valve_change 017.jpg
I think we are getting somewhere now!
Remove the six visible electrical connectors from the electro-valves. They are tight but there is only lugs holding them to the electro-valve connectors, no clips.
You can see 3 torx head bolts on one side and 4 on the other holding a cover on the valve body in place. These 7 bolts also hold the valve body onto the transmission. There is a better view of the particular bolts I am talking about in the next post.
valve_change 018.jpg
Remove the single bolt indicated in the photo. You can remove the bolt when the valve body is on the car or off the car (now or later). The bolt, the leaf spring and the 'L' shaped washer will then come off the valve body.
Later on, the leaf spring can ONLY be installed when the whole valve body is installed on the car because it needs to be aligned AND you need to remove it to install the new electro-valves. So, yes, you do have to take the leaf spring off!

End of part1. I will break this post in two to make it a bit more consumable. Stay tuned...
User avatar
My Name: Ozvtr

Posts: 957
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
Has thanked: 37 times
Been thanked: 257 times


valve_change 019.jpg
There are 7 screws holding a plate and the whole valve body to the transmission. I have numbered the screws for later notation but you can remove them in any order.
You will need to support the valve body when you are removing the last screws as there are no pins or guides holding the valve body, just the screws.
There are 2 more connectors on 2 more electro-valves on the back side of valve body. Don't forget these before you attempt to remove the valve body completely from the transmission.
Now, remember the manual valve I was so adamant about before? Well now you have to deal with it! It can slide completely out of the valve body, there is nothing holding it in! If you refer back to the very first picture you will see what I am talking about.
valve_change 020.jpg
Note that there are 2 oil seals in the bottom of the transmission. Don't loose them or damage them. Officially these should be replaced but if they still sit proud of the casting they should still be good to re-use.
valve_change 021.jpg
valve_change 022.jpg
The two valves we will be replacing are the valves connected to the last 2 connectors you just undid. The ones at the top, on the back of the valve body. You will also notice that these are the only 2 that are that particular shape . The other 6 are a slightly different shape. Remove them by unscrewing the torx screws on the front of the valve body.Note; the seals on the face of the old valves might stick to the valve body, remove the old seals. The new valves will already have seals installed. If your research has indicated that you need to replace the selector valves ( the 'other' 6 electro-valves), then the valves are held in place by torx screws between each of the valves.
Note that there are NO locating lugs or pins! The valves can be located in any direction, HOWEVER they will be mounted with the electrical connectors upper most! The valve retaining screws are torqued to 9 Newton Metres.
A note here on cleaning the valve body. There are a lot of videos on youtube showing how to disassemble and clean the valve body. You could strip down and clean the valve body with spray parts cleaner, brake cleaner or whatever! However in my opinion you risk dislodging particles and blocking fine galleries. There are check valves, sliders and springs that have been installed and adjusted to produce specific pressures JUST AS IT IS. So you run the risk of upsetting these adjustments.
valve_change 023.jpg
Install the cover and slide 2 of the mounting bolts back into the valve body in positions 4 & 5 .
Next we are going to install the valve body back onto the transmission.
Important: ensure the manual valve is installed and that it is around the correct way. With the axial slot visible! refer to picture #1
Important: Install the 2 electrical connectors for the electro-valves on the back side of the valve body before installing the valve body onto the transmission.
valve_change 023a.jpg
valve_change 023b.jpg
There is a pin descending from the selector quadrant. The pin must engage in the slot around the end of the manual valve. It does not matter where the quadrant or manual valve are located at this time just that the pin is located in the groove as the valve body is installed. Screw up the 2 mounting screws but not tight just yet.
OK. confidence check!!
New electro valves installed and the electro-valve mounting screws torqued up?
2 electrical connectors installed on electro-valves at the back?
Manual valve slides in and out as selector quadrant is moved backwards and forwards? Turn the selector arm on the top of the transmission to move the valve and selector quadrant. The ball joint connector will need to be removed to move the selector quadrant by hand. The quadrant will no longer "click" as the leaf spring has been removed. The action should be smooth.
valve_change 024.jpg
Thread the remaining 5 bolts into the the valve body. Tighten all the bolts in the numbered sequence to 9 Newton Metres. Back off the bolts but dont make them loose!! Re-torque to 7.5NM. YES, 9 then 7.5 NM!
valve_change 024a.jpg
Re-attach the 6 remaining electrical connectors.
valve_change 025.jpg
Re-install leaf spring, 'L' shaped washer and retaining bolt. Don't worry where the spring is located at this time and don't fully tighten the retaining bolt.
valve_change 025a (2).jpg
If you haven't already, pop the ball joint socket off the selector shaft. Rotate the selector arm all the way clockwise to the #2 position.

It is very difficult to explain what you need to achieve in setting up the relation ship of the leaf spring and the detentes in the selector quadrant. But the selector quadrant needs to be hard up against the fully counter clockwise stop when the leaf spring locator is in the last detente of the selector quadrant.
Note: when the selector ARM on the TOP of the transmission is rotated counter clockwise, the selector quadrant inside the transmission rotates clockwise!!!!
The problem is; that as you screw down the retaining bolt for the leaf spring it tends to push the quadrant off the stop and twist the leaf spring! There is a special tool that "squashes" (preloads) the leaf spring against the valve body and holds the spring in position as you make adjustments to the location of the quadrant and locator on the spring. The "locator" is the pin in the spring jaws that locate into the detentes in the selector quadrant. See picture 025a.
valve_change 025a.jpg
valve_change 025b.jpg
valve_change 026.jpg
The process can be done without this special tool but you need to be aware of 2 things.
1) the spring locator needs to be (approximately) centered on the selector quadrant. Top to bottom.
2) when the spring is tightened down with the retaining bolt, there is NO slop in the selector arm at the #2(fully CW) position.
It may take several goes to get the alignment right.
The tool Jagpurr made up is only partially correct. The tool also needs to push the leaf spring almost flat while centering it on the selector quadrant. His tool only centers it top to bottom.
EDIT: There is a third post in this thread (below) showing a make-shift arrangement to preload the leaf spring for adjustment.

By the way the #1 and #2 positions I have indicated on the pictures above are NOT used on the C3 but the selector is set up to the #2 position for alignment purposes. In those vehicles the #1 position is 3rd gear and the #2 position is 2nd gear. First gear is selected by a push button. Most "modern" AL4 equipped cars have a "manual mode" in the drive position to select any gear, sequentially.

At this point you can continue on with the alignment or take your chances that the shifter linkage has not moved out of alignment. Remember what I said way back in the beginning about removing the ball joint?
Rotate the selector arm on the top of the transmission to the neutral position.
You can pop the ball joint back on and you can see if the alignment has been retained (only for those who don't want to do the alignment).
valve_change 027.jpg
If (later) you put everything back together and the gear selector flashes when some positions are selected, then you will need to continue with the alignment.The quadrant and selector switch are out of alignment.
If you are going all-out, then you should perform the alignment irrespective of whether you think you haven't disturbed anything or not.

The alignment:
valve_change 028a.jpg
Make sure the gear selector in the cabin is in neutral. If necessary, rotate the selector arm on the transmission to the 'N' position.
valve_change 029.jpg
valve_change 030.jpg
loosen the two retaining screws for the selector switch assembly so it can swivel around the selector arm shaft. Using a mulimeter or some device to check a short circuit, look for continuity across the two exposed contacts on the switch. Move the entire switch backwards and forwards to find the spots where the switch contacts are open circuit (off in the diagram). Find the mid point where there is continuity (on) and lock the two switch retaining screws down.
valve_change 031.jpg
valve_change 032.jpg
valve_change 33.jpg
on the blue selector arm ball joint socket there is a yellow clip. Pull it upwards off the body of the socket. The socket is spring loaded on the shaft and it may pop outwards. Replace the cable retainer onto the bracket. Snap the ball joint socket back onto the selector shaft ball joint. Push the blue ball joint socket down until the two ears of the orange retainer pop out.
Push the yellow retainer back into the ball joint socket to lock the socket onto the selector cable.
Now, the gear selector, the selector switch, the selector quadrant and the manual valve should all be lined up in neutral!
The transmission cover can now be fitted and the screws are torqued to 9 Newton Metres.
Refit the gearbox ECU mounting plate. Remember to be careful with the smaller mounting screw on the left hand side.
Install the gearbox ECU electrical connector and the plastic cover.

The final points are to install the coolant hoses (if removed), fill the engine with coolant (if required) and to re-fill the transmission oil. Sorry but as I explained in the beginning, I wont be covering that.
valve_change 027.jpg
Finally, It's possible that after replacing the ball joint onto the switch arm your gear selector display will flash. If so try re-positioning the switch using the above alignment procedure...again.

A few comments: just because an electro-valve is brand new doesn't mean it's good!!! I have seen a brand new valve prove to be faulty! So if the above procedure doesn't work you may need to try new valves. Having said that as I said earlier, the electro-valves are by no means the only thing that can go wrong with the transmission. Replacing the valves is something to try but it's not guaranteed to fix your gearbox problem.
User avatar
My Name: Ozvtr

Posts: 957
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
Has thanked: 37 times
Been thanked: 257 times


I have another way to perform the alignment of the selector quadrant and the leaf spring.
After you have installed the leaf spring.
Loosen the spring retaining bolt but don't take it out.
Remove the bolt that is visible through the hole in the leaf spring. Place an over sized washer under the head of the bolt and reinstall it. Screw the bolt down until the leaf spring is flat against the valve body and the bolt is tightened down (just tight,not too tight). Make sure the detente roller is engaged in the number 2 position (the last notch on the left of the selector quadrant). Undo the bolt with the over sized washer, 2 whole turns. The leaf spring is now preloaded with the same tension as if the retaining bolt was tightened up.
roller blade 002.jpg

Now slide the leaf spring and selector quadrant to the right until the selector quadrant is hard up against it's stop and stops moving. With the spring under tension it might take two hands to slide the spring. One to pinch the quadrant and spring and one the help slide the spring.
Make sure the roller remains half way between top and bottom of the quadrant face.
roller blade 003.jpg

Tighten the spring retaining bolt to 9 Newton meters. Remove the bolt and the over sized washer. Remove the washer from the bolt and reinstall the bolt into the valve body. Torque it to 7.5 Newton meters.
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