Replacement of electrovalves AL4 transmission fault code 6

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.
My Name: JAGPURR

Contributor
Posts: 8
Joined: Wed Oct 29, 2014 8:01 pm
Model: C3 2002-2005, Original shape model
Year: 2004 (04)
Engine Size: 1.4
Fuel Type: Petrol
Mileage: 33000
Trim Level: Touch
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD (UK)
Been thanked: 4 times

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How to replace electrovalves in the AL4 transmission to fix fault code 6 (BANG! Transmission)


Replacement of electrovalves AL4 tr...
Replacement of electrovalves AL4 transmission fault code 6




This was a result of intermittent warning lamps on dashboard, consisting of the snowflake and the S flashing together.

Occasionally the gearbox would jolt sharply and slam into 3rd gear. Switching off the ignition would clear the fault until next time.

A check using the Lexia showed fault code 6 pressure regulation, difference/setting.

A search on the internet and this forum pointed to faulty electrovalves in the gearbox, so this is an account of how I changed these to correct me problems.

AL4 gear box view from engine bay
AL4 gear box view from engine bay

A view of the engine bay you cannot even see the gearbox yet ! The black block on the gearbox side is covering the gearbox ecu.

Remove parts to access the AL4 block from the engine bay
Remove parts to access the AL4 block from the engine bay

Air filter and battery tray removed, you may notice the right hand bolt hitting the brake pipes before it was fully out , you will need to gently ease the brake pipes away to remove this bolt.
It was now that I decided to get better access I would remove the water pipes.

AL4 block cover visible with engine bay parts removed
AL4 block cover visible with engine bay parts removed

At last the dog can see the rabbit. With everything removed you can get full access to the gearbox side cover which we remove to gain access to the valves. I decided not to drain all the oil so just placed a tray on the floor to catch the 1.2Ltrs that came out.
You will need a T30 TORX BIT from now on.

Al4 Block cover removed showing magnets
Al4 Block cover removed showing magnets

The cover removed and showing the two magnets that are there to catch any metal filings. You can assess the condition of the box from these. Here they were fine, the box having only done 33 000 miles. Hence not feeling the necessity to replace all the oil.

The valve block revealed.
The valve block revealed.

The valve block revealed, the electrovalves we want are just peeking into view at the top.
If the transmission is out of the car you will need to secure the selector mechanism to ensure the selector does not move, but if still in situ just leave in park.
Firstly examine the spring arm assembly to familiarise yourself with its position, for reassembly. Then remove the bolt top right to release the selector spring arm. You will see a stepped valve shaft at the top behind the spring arm, note how it’s notch aligns with the pin on the bottom of the selector cam.

Unplug the five electrovalves at the side
Unplug the five electrovalves at the side

Unplug the five electrovalves at the side and the one at the bottom and pull wiring to one side.
Remove the seven bolts holding the valve block in place, four on the right of the cover plate three on the left. ( Note the block is now loose so you will have to keep one hand on at all times.)
Remove the cover plate and put to one side. Ease the block down and tip forward from the top. This will let you remove the stepped selector spindle as it is likely to drop out later. Also you need to unplug the two remaining electrovalves before you can separate the complete valve block from the transmission.

The housing with valve block removed
The housing with valve block removed
The housing with valve block removed, make sure you haven’t lost either of the two rubber seals behind the valve block.

The valve block with the stepped selector spindle showing correct orientation.
The valve block with the stepped selector spindle showing correct orientation.
The valve block with the stepped selector spindle showing correct orientation.

Replace both the elecrovalves shown with an arrow
Replace both the elecrovalves shown with an arrow

The valve block turned over the electrovalves we want are at the top (arrowed).

AL4 Valves view close up
AL4 Valves view close up
A close up of the valves to change. (You can get from the dealers for £200+ or here like me).

The two T30 TORX screws holding the valves in place.
The two T30 TORX screws holding the valves in place.
The two TORX T30 screws holding the valves in place.

The old valves at the bottom new at the top.
The old valves at the bottom new at the top.
The old valves at the bottom new at the top. Luckily mine are identical so no further software updates are necessary. (Therefore I can confirm that this is good news for anyone with a car 2004 or later). If your old valves have a white plastic electrical socket these are the old style and where replacing with the black Borg-Warner type you must update the software.

Should anybody find that their car is fitted with the black valves and is earlier please let everyone know so we can perhaps ascertain when the change over took place

Reassembly is reverse of removal. Don’t forget to plug in the two top electrovalves and ensure you replace the spindle and align the notched end with the pin on the bottom of the selector cam. Take care not to trap any wires when bolting the block in place and check you have plugged in the remaining six valves.

Alternative to special alignment tool 'M1'
Alternative to special alignment tool 'M1'
The reason I mentioned familiarising yourself with the spring arm earlier is if like me you didn’t buy the special alignment tool you will have to come up with a way of repositioning it upon assembly.
I used a bolt and luckily found a spacer the right size to fit the hole in the arm.

alternative special tool in situ (arrowed)
alternative special tool in situ (arrowed)
The bolt and spacer doing its job. Actually I think if you take care and tighten the mounting bolt slowly you could do it by eye. Just ensure the arm is square and the roller end located firmly in the first notch of the cam.

A mirror view of the AL4s arm centralizing hole showing the bolt you need to remove.
A mirror view of the AL4s arm centralizing hole showing the bolt you need to remove.
A mirror view of the arm centralizing hole and the bolt you need to remove to fit the special tool or whatever you made to do the job.


I strongly recommend watching the series of four videos on youtube of this procedure.

They are in Russian but show exactly what to do. They also show dismantling and cleaning of the valve block but in my case I did not feel that this was necessary so omitted it.

As mentioned I only replaced the oil lost so reset the oil counter as follows using the Lexia.
Previous reading = 8827, subtract 2750 per 0.5 litres of new oil (here - ESSO LT71141) added, so changed reading to 3327.

(The max reading before oil change due is 32958 so you can see my oil was far from worn out.)

I was pleasantly surprised how straight forward the procedure was . Most of the chew was actually getting to the transmission cover. This was on a Citroen C3 1.4 2004 other models may be easier or worse but it’s well worth having a go and saving yourself £500. JAGPURR ;)




EDIT:
Further reading on another AL4 electro-valve replacement guide with more pictures and a much deeper look into the problems of the AL4 transmission.
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