W202 722.6 Tranny

[benzonline]

Hi, just have a question as this forum is very knowledgable for the W202 chassis.

Yesterday I solved my loss of power issues finally with a new MAS. The car flies but then today it is shifting funny...holding the gears too long and then harshly shifting into each one...but its intermittant and if u use full throttle its smooth shifting.

Never did this with the old MAS...is it possible its still training itself? ATF change is my next priority!

Thanks so much....its a 99C230K with about 80 000kms.

 

[R2D2]

try driving it in w mode for a few hours then s mode again.........

 

[benzonline]

I was thinking maybe I screwed up the "re-learning" process. Mechanic told me to drive it locked in 2nd gear for a bit so I did and then drove regularly but mostly high speeds and high revs as the power was all back and I was having too much fun!

Its been 150kms with the new mas already.

 

[nickmann]

The adaptive shifting learns after 5 or so occurences of each shift, so it has finished training itself. When I changed my MAS the workshop asked me to bring it in to reset the ECU, maybe you should have this done?

 

[benzonline]

Resetting was done of the ECU and codes cleared when the new MAS was put.

They had it plugged in where the slot is in the front to check the codes and cleared....this would be resetting the ECU right?

 

[silverarrow]

i would suggest you change the atf and also filter and gasket and re set the gearbox counter this has a big effect on the shift pattern

 

[benzonline]

Yes I'll have to setup an appointment for that.

 

[nickmann]

Resetting was done of the ECU and codes cleared when the new MAS was put.

They had it plugged in where the slot is in the front to check the codes and cleared....this would be resetting the ECU right?

I believe that reading the codes and a reset are two different jobs. They may or may not do a reset as a matter of course.

If it were me I would book it in for an ATF+filter change, explain the harshness and ask for the reset to be done whilst they have it. Then go from there.

 

[mobeyone]

I agree, a full reset of ecu will be required when changing MAF/MAS/AFM or whatever you want to call it!

 

[benzonline]

ok great guys! This forum is great for help even though im not in the UK but Canada.

Should dealers only perform ATF changes? Might aswell since I will need computers as part of the job. They will probably charge me alot extra for the resetting!

 

[mobeyone]

I am looking for a good indie to do my atf change.... still looking...

As for the ecu, should be whatever they charge for an hour and not more than that - and go through each section clearing all codes.

 

[benzonline]

Just booked it in at MB...earliest was 2 weeks from now and I asked the service advisor about the computer...he said it will be reset and re-calibrated.

 

[panason1c]

Found this on another site...tried it on my ML and it works!...............


Resetting auto gearbox memory without disconnecting battery..

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Found this on the US MB slk forum... was a little scepticle at first until loads of guys reported that their cars were quicker off the line, changed gear at more optimum points etc, so I tried it and it does indeed seem to work!

The long way to reset the gearbox memory is to disconnect the battery for 30 minutes - but follow this quick procedure and it can be done in a couple of minutes!! Give it a try yourselves and post the results if it works!!

" 1. Get in your car, it doesn't matter if you close the door or not.

2. Turn the key to the on (not start) position, the position just before the starter turns over.

3. Press the gas pedal to the floor with the key in the "on" position.

4. Hold the pedal to the floor for five seconds, then turn the key back to the "off" position (don't remove the key), then release the gas pedal.

5. Wait 2 mins for a full alignment.

6. Drive the car as you always do.

 

[benzonline]

Well I printed out those steps and tried it...transmission acts the same and I followed the shifting...its the 3rd gear which it likes to stay in for awhile if you keep the speed constant then eventually shifts to fourth and goes good from there or if you speed up it will shift.

Shifts are also rough and you do feel them....It feels like the hydraulic transmission in my friends W202 C220 1994 and his keeps the 3rd gear longer aswell!

 

[Dieselman]

The symptoms are typical of a tired MAF. Have the dealer check the new MAF to be sure it's Ok.

 

[benzonline]

I wil be mad if the new MAF is bad. Everything works otherwise and I get the car's full power except for the shifting troubles.

Funny thing, with the failed MAF I had the car shifted perfectly and smoothly.

 

[benzonline]

Another forum member msged me and wrote:

You can reset the adaptation YOURSELF.
IF you follow this procedure the trans WILL re-learn!
ALL shifts must happen below 1900 RPM!!!
Select 1st gear & slowly accelerate thru the gears upto 5th & then coast back to a stop. DO that 4 times & then let the car sit at idle for 10 minutes! After idling for 10 minutes shut off for 1 minute.
AT that point the trans adaptation should take place.
Good luck

I will try this today.