Hi to you all, I am a new convert to MB but I have a problem! I drive an S320 CDI 2001. The problem is, after driving for a while at motorway speeds ( 5-15 mins) the car starts changing up at 2k through all gears no matter where the pedal is pressed (no kick down), until top gear when it will creep up to 3k. If I stop the car for a few minutes and restart it will be fine again until I drive firmly up or to motorway speeds again. If I manually change gear it will hold in gear but feels reluctant to rev. The ESP and BAS warnings come on every now and again, I have been told this is caused by a faulty brake light switch, got one coming. The car has covered 220k miles and is very responsive at all other times. Any advice gratefully accepted, many thanks, Danny
Buggerlugs
Active Member
Sounds like the trans control module is responding to a degraded or missing signal, first port of call is to plug in the Star machine and run a diagnostic check, no real progress can be made till then.
I had the same problem but it coincided with my alternator failure so it was due to low voltage on the management systems.
You really need to plug the car into STAR and check all the readings.
You can also read off the STAR machine the change times from first through each gear to fifth. This should give you some indication on the health of the gearbox.
You really need to plug the car into STAR and check all the readings.
You can also read off the STAR machine the change times from first through each gear to fifth. This should give you some indication on the health of the gearbox.
Thank you all for the advice, this is what I did, it started to go into limp mode and also get stuck in any gear it fancied, after several star checks they said I needed a new selector control module, a new MAFF sensor, Air filter and change the gearbox oil and filter. I had them do all apart from the selector control as this was a big lump of cash, after them doing the work it was much better ie smooth changes and no limp mode for 1 day (Aargh). Then it stared to get stuck in gear even worse, I took all the control module to pieces and cleaned all the sensors within and mended the broken case mount etc, put it back together (if anyone wants more detail please ask I saved £550) and hurray it all worked fine except now if I go anywhere near a dual carriageway for more than five minutes it goes in to limp mode again and again even after stopping to reset by turning off the ignition. Is this anything like your situations, I would be eternally grateful if you could shed any light on what to do or try. They have the star machine and then seem to guess with my money. I look forward to your reply.
Sorry I should have added, after fidling with a few bits, mended a slight leak from the fuel rail banjo and possible split pipe going to the EGR valve, thinking this would help (wrong). I did notice that whilst stationary if you hold the revs at 2500 all seems well until it then starts to smoke not a huge amount but certainly enough to notice and it smells of unburnt diesel! I was wondering if this could be the limp cause as this rev range would suggest dual carriageway speeds and could well be clogging up a sensor etc. Any ideas? I will get a new fuel filter and fit it, it cannot do any harm as I am suspecting the so called service chap from the previous owner was not doing all as required, bless him. Thank you all in anticipation.
