C5 4HP20

[pavlebo]

Running Lexia I got the error: Gear 3 incorrect coherence?

Sent from my GT-N8000 using Tapatalk HD

[Mandrake]

Running Lexia I got the error: Gear 3 incorrect coherence?

Sent from my GT-N8000 using Tapatalk HD

Are you sure the replacement gearbox has the same final drive ratio ? What model of car did it come from ? There is more than one final drive ratio for the 4HP20 depending on the model of car it's fitted to and the ECU will be unhappy if the ratio is wrong.

Does it actually drive ok despite the error ? Try putting the front of the car on axle stands so the front wheels can spin in the air, putting it in gear and measuring the gearbox input and output speed sensors with the Lexia using parameters measurement under diagnostics.

If you select snow mode you can manually engage 1st, 2nd, 3rd even at slow speeds and work out the gear ratios from the measured speeds...

[Ben82]

Running Lexia I got the error: Gear 3 incorrect coherence?

Sent from my GT-N8000 using Tapatalk HD

Are you sure the replacement gearbox has the same final drive ratio ? What model of car did it come from ?

Does it actually drive ok despite the error ? Try putting the front of the car on axle stands so the front wheels can spin in the air, putting it in gear and measuring the gearbox input and output speed sensors with the Lexia using parameters measurement under diagnostics.

If you select snow mode you can manually engage 1st, 2nd, 3rd even at slow speeds and work out the gear ratio from the measured speeds...

Unfortunately selecting the manual mode on the C5 turns off snow or sport mode. e.g in snow mode and switching to manual it'll drop down the gears from 3rd back to 1st (and won't let you back up to 3rd if your speed isn't high enough)

[Mandrake]

Ben: I mean manual mode then.

On the Xantia snow mode with the lever in 1st, 2nd or 3rd IS manual mode...if the C5 has a manual mode of its own, that's what needs to be used - something that will let you change up into 2nd and 3rd when the wheels are turning slowly..

[pavlebo]

It was a little hard to find auto adaptive reset, in my version of the Lexia, it is under Diagnosis, auto gear ... (ver. 7.2). After reset I deleted error: Gear 3 incorrect coherence. I drove a test drive for about an hour with frequent changes the gears. Now Lexia show no faults in auto gearbox ECU. Tomorrow I will check it again.
Gearbox is full of red oil, in old one it was black in color. I am still waiting for new oil. I have just finished cleaning of the old gearbox and I will try to dismantle it next week.

Thank you all!

[Peterdb]

means the cost of the Lexia has paid out already as in the garage it would have cost you a fortune!!!!
Anyway, good I have an Aisin 6 gear aut and until now don't have this problem but must admit after 350K I changed oil from the gearbox with a special machine my garage in Holland <Johan van Oldenhage> has developed this machine and can change ALL oil in one go and it works (for the gearbox). After refresh the gearbox was much more quiet and goes smooth in all gears and back!!
So the slogan that oil in the gearbox is for "life time" you can forget. I would recommand anyone with a aut. gearbox to do so, not sure in the UK they have such a machine.

[CitroJim]

I would recommand anyone with a aut. gearbox to do so, not sure in the UK they have such a machine.

Yes, this is available in some parts of the UK. It is called a 'Hot Flush' and several members have reported good results using this method..

[Mandrake]

It was a little hard to find auto adaptive reset, in my version of the Lexia, it is under Diagnosis, auto gear ... (ver. 7.2). After reset I deleted error: Gear 3 incorrect coherence. I drove a test drive for about an hour with frequent changes the gears. Now Lexia show no faults in auto gearbox ECU. Tomorrow I will check it again.
Gearbox is full of red oil, in old one it was black in color. I am still waiting for new oil. I have just finished cleaning of the old gearbox and I will try to dismantle it next week.

Was the fault code Gear 3 incorrect coherence already there before you drove the car with the replacement gearbox fitted ? If so it was remembered from your faulty gearbox.

I would be quite concerned about the gearbox being full of red oil - almost certainly it will be Dexron II or III which will damage the gearbox fairly fast as this gearbox can only use LT71141. You want to get that oil out of it and get the correct stuff in ASAP.

The problem is a manual oil change (drain and fill) will only replace 50% of the oil each time so you can never fully remove the old oil this way, only dilute it by half for each change. Thus it would take at least 3 oil changes (with some driving between each change) to sufficiently dilute the red oil. Three changes is about 12 litres of oil...

If you can find someone who can do a "hot flush" it would be highly recommend despite the cost, as this is the only way to quickly and completely remove all the old oil and replace it with the correct oil, but this too will take approx 12 litres of oil even though the gearbox only holds about 8 as there is some initial mixing during the process...(the machine keeps removing old oil and injecting new oil through the heat exchanger loop while the engine is idling until what comes out is clean and the correct colour)

[CitroJim]

I've seen a similar fault once before on a V6 Xantia and it was caused by an incorrect set of final drive ratios..

My fault. I rebuilt the 'box with a final drive from a 2.2HDi HP20 and the Xantia ECU saw that it was all wrong...

I had to re-rebuild the box with the correct final drive...

I concur with you on the oil Simon and if it's had Dexron in it then I'd definitely try to get a hot flush as it's imperative to get rid of all of it...

[pavlebo]

All gears on automatic gearbox work fine. I have change 50% of oil in the gearbox, around 4 l.
I can not obtain "Hot flush" in my country, and oil was problem. No errors in auto ECU.

[pavlebo]

Is oil atf 4hp20 , marked with peugeot and citroen symbols , made in germany, no esso symbol on it, same as lt71114?

[pavlebo]

I find this oil in one shop in Montenegro!

[Hell Razor5543]

Give it time. Somebody with the relevant knowledge (probably addo or CitroJim) will be able to let you know. I do see what you mean, though.

[CitroJim]

Is oil atf 4hp20 , marked with peugeot and citroen symbols , made in germany, no esso symbol on it, same as lt71114?

Yes it is... It'll be likely marked as ATF AL4 4HP20 if it's the same stuff as we get in the UK but yes, if it's genuine Peugeot/Citroen stuff obtained from a dealer then it'll be the stuff..

Another way is to look at the ATF in the bottle. It'll be a light straw colour and smell revolting - a bit like cat's pee...

[Mandrake]

9730 AE looks like a PSA part number - it should be possible to look up this number and see if it's correct.