Problems With Auto Box?
Discussion
Hi all, the problem started on my 2006 2.1 CDI estate c class car after a run back home from the east coast, some 60 miles.
I had slowed the car down to enter a roundabout, then accelerated to move round the roundabout and on to a dual carraigway, then the problem started, the engine revs were slow to pick up because it was changing up a gear at revs around 2,000 rpm. And any more throttle respons did not rev as normal and again it changed to a higher gear or that is what seemed to happen and totally make no difference to increase engine revs no matter how much the pedal was depressed.
Imagine having a manual gearbox and keep changing the gears up without the car speed increasing much, and you will end up with the engine overloaded as gearing is too high for the car speed, thus no matter how much throttle is given the engine revs will not rise.
This is just what seems to be happening.
I stopped the car, ignition off selected C mode as I was in S mode, started car and the car seemed to drive OK but the rev counter was slightly on low side before gear changes, but the car was driveable, and got home safely.
I thought that would be OK left in C mode, but after a few days the same problem was back and I thought first thing to do was change the oil and filter in the Auto box. So the oil and filter was changed, do not know if it has been changed before,as MB seems to think that the oil will last the life of the car. Car milage 116,000 miles
Cut a long story short I still have same problem. So I thought disconnect battery for 30 mins and see if it may reset if its a electric problem. Took the car out and it was great, proper revs before gear changes and rapid progress in speed. I am thinking sorted, stopped the car after running it about 4 miles while wife and I have meal at a restaurant.
Started car and within 1/4 mile symptoms back again. When I got home, I put the gear lever in nuetral and reved engine would not go passed 3,000 rpm, but in park and same thing.
Stopped engine, and restarted in park, the engine would rev all the way round the clock with ease, put in neutral and once again rev round the clock. Stopped car and that is now parked up untile I drive it again.
So sorry for the lengh of report, but I thought the more info the better someone will be able to help.
Thanking in advance for any help sorting the problem.
Ade
I had slowed the car down to enter a roundabout, then accelerated to move round the roundabout and on to a dual carraigway, then the problem started, the engine revs were slow to pick up because it was changing up a gear at revs around 2,000 rpm. And any more throttle respons did not rev as normal and again it changed to a higher gear or that is what seemed to happen and totally make no difference to increase engine revs no matter how much the pedal was depressed.
Imagine having a manual gearbox and keep changing the gears up without the car speed increasing much, and you will end up with the engine overloaded as gearing is too high for the car speed, thus no matter how much throttle is given the engine revs will not rise.
This is just what seems to be happening.
I stopped the car, ignition off selected C mode as I was in S mode, started car and the car seemed to drive OK but the rev counter was slightly on low side before gear changes, but the car was driveable, and got home safely.
I thought that would be OK left in C mode, but after a few days the same problem was back and I thought first thing to do was change the oil and filter in the Auto box. So the oil and filter was changed, do not know if it has been changed before,as MB seems to think that the oil will last the life of the car. Car milage 116,000 miles
Cut a long story short I still have same problem. So I thought disconnect battery for 30 mins and see if it may reset if its a electric problem. Took the car out and it was great, proper revs before gear changes and rapid progress in speed. I am thinking sorted, stopped the car after running it about 4 miles while wife and I have meal at a restaurant.
Started car and within 1/4 mile symptoms back again. When I got home, I put the gear lever in nuetral and reved engine would not go passed 3,000 rpm, but in park and same thing.
Stopped engine, and restarted in park, the engine would rev all the way round the clock with ease, put in neutral and once again rev round the clock. Stopped car and that is now parked up untile I drive it again.
So sorry for the lengh of report, but I thought the more info the better someone will be able to help.
Thanking in advance for any help sorting the problem.
Ade
Sounds vaguely similar to the issue I had with mine, though mine is a 2013 E220 (similar engine?).
On mine the sensor that tells the car to re-gen the DPF had failed so the DPF had filled to 200% of its normal “full” level.
Car suddenly lacked power and wouldn’t rev much, and was slow to change gear when pulling away from a set of lights. I left it for a while and all seemed well, but it came back. I couldn’t really get the car past about 60mph on the drive home but everything sounded ok except for a slight whistle. I thought it was a boost leak. I had no warning lights or messages.
My local MB specialist was able to plug it in and see the DPF was clogged. Sensor was changed and a re-gen forced and it was sorted. The exhaust whistle was due to the back pressure.
I assume yours has a DPF? Worth a check?
On mine the sensor that tells the car to re-gen the DPF had failed so the DPF had filled to 200% of its normal “full” level.
Car suddenly lacked power and wouldn’t rev much, and was slow to change gear when pulling away from a set of lights. I left it for a while and all seemed well, but it came back. I couldn’t really get the car past about 60mph on the drive home but everything sounded ok except for a slight whistle. I thought it was a boost leak. I had no warning lights or messages.
My local MB specialist was able to plug it in and see the DPF was clogged. Sensor was changed and a re-gen forced and it was sorted. The exhaust whistle was due to the back pressure.
I assume yours has a DPF? Worth a check?
If it has a DPF, could certainty cause the issue mentioned above. You can throw two bottles of Forte DPF fluid into the fuel tank. Took my old CLK from 110% full to 30%. A forced regen and another bottle later saw it sitting at zero.
Just to rule out a bad sensor I replaced the sensor too.
Just to rule out a bad sensor I replaced the sensor too.
I doubt if a 2006 car will have a DPF.
Did you flush the torque converter when you did the fluid change, this holds quite a lot of oil, ie 4 litres or so. If not you have a mix of old and new oil which could still affect the gearbox/torque converter operation.
Did you flush the torque converter when you did the fluid change, this holds quite a lot of oil, ie 4 litres or so. If not you have a mix of old and new oil which could still affect the gearbox/torque converter operation.
Edited by Monkeylegend on Saturday 1st February 19:21
Monkeylegend said:
I doubt if a 2006 car will have a DPF.
Did you flush the torque converter when you did the fluid change, this holds quite a lot of oil, ie 4 litres or so. If not you have a mix of old and new oil which could still affect the gearbox/torque converter operation.
Garage did it so i dont know.Did you flush the torque converter when you did the fluid change, this holds quite a lot of oil, ie 4 litres or so. If not you have a mix of old and new oil which could still affect the gearbox/torque converter operation.
Edited by Monkeylegend on Saturday 1st February 19:21
Ade
Sounds like it might be going into limp mode - there's no indication it does this, other than the performance being way down and the revs limited. Mine (2005 model C270CDi) has done it a couple of times when it's not been used for a while as one of the (many) things that triggers it is the voltage dropping below 9V on start up. Mine resets once it's been driven for a few mins and stopped and restarted.
The engine and gearbox interact with each other and you really need to take it to a Merc indie and get the codes read, otherwise you'll end up chasing your tail. Hopefully it'll be some relatively minor thing. If you don't know a Merc indie, there's a list of some of them at the top of this sub-forum, or post up your location and someone may know a local one to you.
MAF sensor failing is one common cause.
The engine and gearbox interact with each other and you really need to take it to a Merc indie and get the codes read, otherwise you'll end up chasing your tail. Hopefully it'll be some relatively minor thing. If you don't know a Merc indie, there's a list of some of them at the top of this sub-forum, or post up your location and someone may know a local one to you.
MAF sensor failing is one common cause.
Hi guys, Great news, after all your comments given indicating it may be the DPF I went on Youtube and watched a video called
"How to do a manual regeneration completed" by a West Yorkshire guy.
And so I thought I would give it a try, the vehicle he was doing it on was a manual gearbox, so to replicate as near as possible I used the Trip tronic in S mode. So I set off driving and getting the rpm to 4,000 rpm then changed up to next gear up to 4,000 rpm until I could get on the Motorway.
Then I progressed up through the gears doing the same until I was doing 70mph which was exactly 4,000 rpm, put cruise control on at this setting and drove from start to 50 miles, then I turned round and drove the Motorway back home in normal "D" mode at 70 mph.
Now before turning round to go home the mpg started from home at 22.3 mpg and while driving in the Trip tronic as stated above the mpg slowly rose to 27.8mpg.
So I drove for 25 miles on my way home,then turned off on to "A" roads for the rest of journey home using "D" mode and driving as
you would nomally stopping at rounabouts junctions etc and observing all speed limits.
The gear changes were smooth and changed gears up and down as it should, climbing hills was easy and when using kick down the car shot off quickly even on hills. when removing foot from throttle approaching roundabout etc in the past the car would retard quite a lot, but now I have to use the brake as engine brakeing seams very little now. HaplessBoy mentioned he was getting a whistle noise when slowing down,so was I, but not now.
So the car seems to have the fault cured, Cannot thank you guys enough and also the guy that did the video.
I will take the advise and put one dose of DPF cleaner and regenerator into the fuel tank to finally clean any remaing contaminents.
I will keep my fingers crossed now and see if the cure remains for the next few journeys and report back.
Summing up for the price of 3 gallons of fuel this seems to be a cheap repair, especially when if the car had gone to some garages they would have said it wants a new DPF at hundreds of pounds plus labour.
Hope this will help you and others reading this to try above and hopefully sort a DPF problem.
Ade
"How to do a manual regeneration completed" by a West Yorkshire guy.
And so I thought I would give it a try, the vehicle he was doing it on was a manual gearbox, so to replicate as near as possible I used the Trip tronic in S mode. So I set off driving and getting the rpm to 4,000 rpm then changed up to next gear up to 4,000 rpm until I could get on the Motorway.
Then I progressed up through the gears doing the same until I was doing 70mph which was exactly 4,000 rpm, put cruise control on at this setting and drove from start to 50 miles, then I turned round and drove the Motorway back home in normal "D" mode at 70 mph.
Now before turning round to go home the mpg started from home at 22.3 mpg and while driving in the Trip tronic as stated above the mpg slowly rose to 27.8mpg.
So I drove for 25 miles on my way home,then turned off on to "A" roads for the rest of journey home using "D" mode and driving as
you would nomally stopping at rounabouts junctions etc and observing all speed limits.
The gear changes were smooth and changed gears up and down as it should, climbing hills was easy and when using kick down the car shot off quickly even on hills. when removing foot from throttle approaching roundabout etc in the past the car would retard quite a lot, but now I have to use the brake as engine brakeing seams very little now. HaplessBoy mentioned he was getting a whistle noise when slowing down,so was I, but not now.
So the car seems to have the fault cured, Cannot thank you guys enough and also the guy that did the video.
I will take the advise and put one dose of DPF cleaner and regenerator into the fuel tank to finally clean any remaing contaminents.
I will keep my fingers crossed now and see if the cure remains for the next few journeys and report back.
Summing up for the price of 3 gallons of fuel this seems to be a cheap repair, especially when if the car had gone to some garages they would have said it wants a new DPF at hundreds of pounds plus labour.
Hope this will help you and others reading this to try above and hopefully sort a DPF problem.
Ade
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