W203 Autobox fault

W203 Autobox fault

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Old Merc

Original Poster:

3,537 posts

172 months

Wednesday 13th July 2022
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My lovely old shed is irritating me. 2002 C270 CDI with 105K on the clock. Its been well looked after, no major problems, gearbox internal filter and fluid change at 70K miles. Drives as sweet as a nut, regularly does over 50mpg.

99% of the time the gearbox wont kick down. Goes through the gears OK, just done a long fast journey at 70-80 no problem. I come wizzing into a roundabout, flat to the floor after, and the engine just labours in 5th gear, takes ages to get up to speed again.
Also there is a strange feeling when manoeuvring or crawling in traffic with my left foot on the brake pedal and a touch of the accelerator. Touching the brake seems to kill the engine?

I suppose the first call will be a professional with the correct Mercedes diagnostic kit. Before I do I thought you "Merc Men" would be able to give some advice.

Old Merc

Original Poster:

3,537 posts

172 months

Saturday 16th July 2022
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I thought I would give you an update on this problem. There's me thinking I have a problem gearbox, turns out its nothing to do with the autobox.

I took the car to https://autosolutions-newbury.co.uk/ they gave it a full diagnostic check that showed a faulty engine Air Mass Sensor. Fitted a new O/E Hella unit, cleared the codes and never touched any of the gear box settings.

It drives like another car, goes like a rocket, gearbox kicks down as it should. This shows its always the best policy to get an expert with the right diagnostic kit to do a full check first. Mike at Autosolutions explained to me that if you start reprograming all the auto gear box settings on an old car with 105K on the clock, you can create more problems. In other words "don't fix what isn't broke"


niva441

2,020 posts

236 months

Saturday 16th July 2022
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Well done on getting it sorted. Shows that the experience of specialists is worth their rate.

lowdrag

13,011 posts

218 months

Tuesday 19th July 2022
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Drove my C220 CDi to 350,000 kms and apart from changing the gearbox oil and filter twice had only one problem which was replacing the aircon pump. Now on a 204 and first problem in 170,000 kms being a wheel sensor. Tough old birds these.

Old Merc

Original Poster:

3,537 posts

172 months

Wednesday 20th July 2022
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lowdrag said:
Drove my C220 CDi to 350,000 kms and apart from changing the gearbox oil and filter twice had only one problem which was replacing the aircon pump. Now on a 204 and first problem in 170,000 kms being a wheel sensor. Tough old birds these.
Your right, this is the first technical fault since new. Nothing has been replaced other than normal service and MOT wear and tear items. Same with my 1997 SL R129, nothings ever gone wrong, it still has the original exhaust system!!

Sheepshanks

34,187 posts

124 months

Wednesday 20th July 2022
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Old Merc said:
Also there is a strange feeling when manoeuvring or crawling in traffic with my left foot on the brake pedal and a touch of the accelerator. Touching the brake seems to kill the engine?
I had a C270CDi and it did this - I think most cars kill the gas if the brake pedal is pressed. I think the only time I needed to do it was after driving through water - I don't recall ever doing it, or feeling I needed to do it, in other circumstances.

I thnk once you're on the brake you can then accelerate - there's some control thing about "last good input".

lowdrag

13,011 posts

218 months

Wednesday 20th July 2022
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Reprogramme your driving style.to use only the right foot. Taking your foot off the brake pedal allows the car to creep forward assuming lever is in D. On my 204 pressing the brake pedal hard brings up "HOLD" on the dash display, leaving both feet free until you touch the accelerator.

ETA:- I assume you are turning off the stop/start every journey? If not, you'll spend a lot on batteries over the years. My 203 was sold on after 12 years with the original and the current 204, (we have two, one 2012 and the other 2014) are both on their original batteries. In fact, thinking back, I am not sure I have had to buy a battery for any of my Mercs in 28 years, and that's only four cars in all, two of which we still have.

Edited by lowdrag on Thursday 21st July 04:22

Old Merc

Original Poster:

3,537 posts

172 months

Friday 22nd July 2022
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lowdrag said:
ETA:- I assume you are turning off the stop/start every journey? If not, you'll spend a lot on batteries over the years. My 203 was sold on after 12 years with the original and the current 204, (we have two, one 2012 and the other 2014) are both on their original batteries. In fact, thinking back, I am not sure I have had to buy a battery for any of my Mercs in 28 years, and that's only four cars in all, two of which we still have.
When I bought my 1997 R129 it came with a "cheepo" battery. I had regular problems due to low voltage, the roof light would come on stopping it working, together with the auto roll bar. I had a number of visits to my Merc` Indy to get it all reset. They told me R129`s need a good battery.
So I went to GSF and bought the most powerful, and most expensive, Bosch battery. That was a few years ago, everything has worked perfectly since.

Old Merc

Original Poster:

3,537 posts

172 months

Monday 25th July 2022
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I should have shut up.
The very next day after posting above about a duff battery. I went to start my SL, the battery was right down and it just managed to fire up. BUT !! the roof button light was on so the roof would not work.
And I was booked in a show the next day. aaaaaaarrrrrrrrr ******