W211 E320 722.6 kickdown fault

[Westheath]

Ok whilst I'm sat here trying to stop eating turkey left overs !!!!

I have a fault coming up in the transmission.

P240A the engine speed sent from the engine control unit via the can bus is implausible

And In the ECM CDI3

2045-1Check component L5( crankshaft position sensor ). No signal detected.

The condition the fault occurs under is when the kick down is enabled,
the rpm's go to zero the car holds back then recovers, engine light on,
then car drives normal again.

It looks like the can bus stops sending data to the TCM from the Crankshaft sensor via ECM protecting the gearbox in kick down mode.

Gear box adaptations seem off a bit as its a recon box conductor plate and TC.

Oil level is slightly high (400ml) will be removed when workshops open after Christmas holidays.

Thoughts ?

 

[alexanderfoti]

Would suspect bad connection on, or faulty, crankshaft position sensor. Or dirty flexplate.

 

[umblecumbuz]

Tesco turkey leftovers can play havoc with gearbox internals!

 

[Westheath]

Would suspect bad connection on, or faulty, crankshaft position sensor. Or dirty flexplate.

I have changed the sensor as a matter of course, they are in stock here,
but suspect the fault lies else where as the live data was Ok from it.

Tesco turkey leftovers can play havoc with gearbox internals!

Pah Tesco ............. Georgina was hand reared and fed by the whole family before her festive demise
very tasty and currently in a stew pot.

 

[LostKiwi]

Sounds like a bad connection or wiring fault as the engine moves when you boot it.

 

[Westheath]

Double checked wiring and plug already,
hardly any movement in kick down mode,
I checked it on rolling road when looking for this fault.

 

[alexanderfoti]

What is the implausible value that the ecu is seeing? Freeze frame data should show.

 

[Westheath]

I'm opening back up on Tuesday, will put Star back on it and have a look.

IIRC
The last session showed everything normal in live data,
I was setting the 722.6 adaptations on the RR when I came across the kick down fault.
the old gear box kick down didn't have the fault and
the CPS is protected from getting bashed by the flex plate/ring gear
when fitting the gearbox, even with new sensor the faults still there.

Just a bit weird

 

[alexanderfoti]

Be interesting to see from both ecus.

Wonder if there is a canbus comms fault.

 

[Westheath]

Had the time to follow up on this over the weekend, need the space at workshop.

The wrong gearbox has been fitted and its being over revved/torqued causing the fault.

Customer had the box fitted 6 months ago but never used kick-down or pushed it over 4000 rpm
a second hand gearbox and TQ (not reconditioned as I was originally told)
was fitted by a pretty well known MB supplier .

 

[alexanderfoti]

Aha! So it must have been slipping under hard acceleration?

 

[stumo]

So are you saying it had the wrong NAG 1 fitted? IIRC There are only 2 types of NAG1, "NAG1" and "Large NAG1". The large NAG1 is used for V8 applications and has taller gear ratios and a different bellhousing/pump assembly. To switch them over accidentaly would be quite a feat, considering you would need to take the front half off the box. I would have thought the TCU would have picked this up earlier, but I guess being a Diesel maybe the tolerance built in to the software was enough to allow it at lower revs.

 

[Westheath]

I would have thought the TCU would have picked this up earlier, but I guess being a Diesel maybe the tolerance built in to the software was enough to allow it at lower revs.

It appears that way as everything is normal until the revs reach over 3500rpm, but I suspect the torque converter is having a hand in the problem as well laying the power on.

Will see what's happening when stripped down.

 

[Jim2]

Have what might be a serious problem. This morning, car ( W212 ) started perfectly, and I selected "R", but it was slow to move off...took more revs than it normally does, then when I put it into "D", situation seemed even worse, really had to rev it to get it to move. To the extent that I was nervous moving out of the drive way, and into the traffic. But I got it on the road, and was driving OK, but I got the feeling that it was taking too much revs. It did improve by the time I got into the shopping centre, and I parked it up. Afterwards, it behaved as normal... but now I have an uneasy feeling when I drive it. Had it been a manual transmission, the symptoms were very similar to a clutch slipping.
Any ideas what is causing this? Your advice is much appreciated,
Best Regards, Jim2

 

[ajlsl600]

loss of fluid, trans pump shot. some electroncs Bxllocks mimicking either.

 

[Jim2]

loss of fluid, trans pump shot. some electroncs Bxllocks mimicking either.

That does not sound so good. aljs1600... ..but after a bad start this morning, drove away all day without problem. I had it checked out with a friends OBD2 scanner ( non Mercedes specific) and it did not show any faults. Monday, I will go to the local MB dealership and ask them to do a STAR scan. That should throw some light on the problem. As it did not have stamped service book in it when I bought it one month ago ( salesman said that most have the service details logged on an MB computer ) I cant really say what was done service -wise, but maybe the main MB dealership can access it's history. In any case, I plan to change both the transmission and rear axle oils. Hopefully... this mornings aberration is only an oil change issue.
Thanks for your input aljs1600..... much appreciated !!!
Regards, Jim2

 

[John Laidlaw]

That does not sound so good. aljs1600... ..but after a bad start this morning, drove away all day without problem. I had it checked out with a friends OBD2 scanner ( non Mercedes specific) and it did not show any faults. Monday, I will go to the local MB dealership and ask them to do a STAR scan. That should throw some light on the problem. As it did not have stamped service book in it when I bought it one month ago ( salesman said that most have the service details logged on an MB computer ) I cant really say what was done service -wise, but maybe the main MB dealership can access it's history. In any case, I plan to change both the transmission and rear axle oils. Hopefully... this mornings aberration is only an oil change issue.
Thanks for your input aljs1600..... much appreciated !!!
Regards, Jim2

Maybe also nothing Jim!
These cars can have some weird stuff going on which seem to fix themselves sometimes! I’d be looking at ATF change first I think...

 

[Jim2]

Maybe also nothing Jim!
These cars can have some weird stuff going on which seem to fix themselves sometimes! I’d be looking at ATF change first I think...

My unqualified opinion and gut feeling would be the oil as well, John so I will do that first, assuming that nothing shows on the MB scan. If it throw's a fault, then based on what that shows, I will act accordingly. I agree that modern electronics ARE weird. schizophrenic, bi-polar and most likely some conditions which don't even have a name yet !!!! LOL
Thanks, and Best Regards, Jim2

 

[ajlsl600]

yup stick it on star and go from there ,if yr a long term benz man it would probrably make sence to get yr own , if you can work it out, IT WILL pay for itself cant actually remember but think mine was about 500, with a spare loaded HD . AND its deffo paid for itself with our SL clk and 2 A Class i ok on mechanicals and electrics,not so hot on electronics so it saves me a lot on asprins..

 

[Jim2]

yup stick it on star and go from there ,if yr a long term benz man it would probrably make sence to get yr own , if you can work it out, IT WILL pay for itself cant actually remember but think mine was about 500, with a spare loaded HD . AND its deffo paid for itself with our SL clk and 2 A Class i ok on mechanicals and electrics,not so hot on electronics so it saves me a lot on asprins..

Yes ajlsl600, I agree with you. This is my 1st MB, and if I will become a long term MB man, will very much depend on the results of the Main Dealer STAR scan, but I sincerely hope so !!!! Every MB owner that I know, swears by them... would drive nothing else. I also know that on forums like this...you are hearing mainly about problem Mercedes Benz..which could give the impression that they are junk.. but for every "problem" Merc... there are hundreds, if not thousands that are giving good trouble free motoring, I aim to become one of those, despite my present "Problem" LOL
The STAR OBD2 you purchased for 500, I presume that it's the Chinese one? ( Don't get me wrong..I have nothing against Chinese products...once they work ) As an interim measure, I think that I will get this one ( see pic) what do you think? They seem to be highly recommended on the forum. I can always upgrade to the STAR model afterwards, all going well.
Thanks again for your helpful advice.
Jim2