urgent advice on battery and gearbox fault

[Chiefriley]

Ongoing problem here with 320 clk driving out of gear..only fault code coming up is wheel speed sensor. Abs/asc lights used to come on and off....So update

I parked her up and I have use of another car
Week later...battery dead
Jumped..started straight off..abs/asc lights on
Gear problem there still..revving and not dropping gear
Left 2 days
Again battery DEAD
same issues with gear and lights

I read up how a battery can cause all manner of problems and even affect the transmission.. However I don't want to rush out and buy a new battery if this isn't the issue.

Could this be the answer to the issue that's killing it
How would I know without buying another battery
Would I need to reset the ecu if the battery issue has killed it

Thanks guys really wanna fix this my mercy is at your mercy.lol

 

[jadefox]

I would almost certainly change the battery regardless. Has it ever had a replacement?
My car started to have really strange intermittent faults on various electrics. My first thought was to change the battery but the garage said it couldn't possibly be the battery and kept the car in for 4 days testing this and that.
Eventually they changed the battery and every single issue went away.
If you're already having battery issues then it sounds like you need one anyway!

 

[Chiefriley]

thanks Jadefox well i had the tranny fluid changed and that did nothing...so im really curious, it obviously needs one like you say it shouldn't drain after being stood for a few days..

 

[Chiefriley]

would i need to reset the ECU or anything though after installing a new battery

 

[Chiefriley]

and alos how would i know if its the battery or maybe the starter relay...sorry for all the questions and the newbie panic.

 

[mad4amanda]

sounds like new battery time

 

[Julesprivate]

Ongoing problem here with 320 clk driving out of gear..only fault code coming up is wheel speed sensor. Abs/asc lights used to come on and off....So update

I parked her up and I have use of another car
Week later...battery dead
Jumped..started straight off..abs/asc lights on
Gear problem there still..revving and not dropping gear
Left 2 days
Again battery DEAD
same issues with gear and lights

I read up how a battery can cause all manner of problems and even affect the transmission.. However I don't want to rush out and buy a new battery if this isn't the issue.

Could this be the answer to the issue that's killing it
How would I know without buying another battery
Would I need to reset the ecu if the battery issue has killed it

Thanks guys really wanna fix this my mercy is at your mercy.lol

It seems logical that if one of the whel sensors is throwing up an error that the ABS and ASC lights would be on, after all the car can't tell what speed all 4 corners are going so it can't control the brakes/traction.

That could be the sensor failing or simply misaligned, but it could also be that the circuit is sensitive to voltage fluctuations and a failing battery is confusing things.

Most modern batteries dislike deep discharge cycles and dependant on the type of battery it's not uncommon for the plates to warp/short and you lose a cell or two - thereby lowering their efficiency and output... causing more problems with sensetive electronics.

Personally, I'd change the battery (or at least swap it out for a known good one temporarily) but I suspect after being left for a couple of weeks (flat) it's probably mullered.

I'd also be surprised if the ECM didn't inhibit at least some of the performance if it detects a speed sensor error, so perhaps those things are related - i assume you mean it's not kicking down as you'd expect?

 

[Chiefriley]

julesprivate hi and thanks, yes it's not kicking down...now to go further, the guy who sold it said he was told it needed the tranny fluid doing so i did it, however with some uneducated guesswork here...

i have access to another car, if i was driving the merc a few days in a row the ABS light would sometimes pop off and the kickdown would happen after say 5 minutes driving.

if i let her stand for a few days the car would start however the abs light was on and the kickdown took longer to find..

complete guess but i'm wondering if the as the battery was slowly dying it was affecting said issues...and now i've let it stand for a week the poor battery has given up the ghost....

 

[CRH71]

With the latest information that you've posted, 100% your battery is failing/failed.

Mine started playing billy suggers, in a very similar manner to your car with oddball, spurious faults and lack of kickdown when my battery was failing last winter. Replaced it and all has been fine (he says, touching wood) since.

 

[Paparazi]

Evening...whatever the fault on the gearbox, first things first.....sort out the battery issue and then tackle the other issues if they are still there.
Personally I would use a cheap car charger and give the blighter a couple of days before taking the vehicle to your local BATTERY SPECIALIST. Note* not a Mercedes dealer.....as a battery specialist will be able to use his 'special gadget' to run a series of battery and charge checks...not a simple and crude drop test.
Probably the battery but you never know if the charge system is at fault.

Martin

 

[jadefox]

would i need to reset the ECU or anything though after installing a new battery

No, I didn't.

 

[Chiefriley]

Thanks guys I'll keep you posted.

 

[Chiefriley]

Update...

Ok so I borrowed a battery of a mechanic he said it was from a big van..lol

Swapped battery and started her up..NO abs lights etc...so I set of driving put her into D and after a few yards..cut out...stop key out then in starts again in D after a few yards cut out???

So I put her into first... Drove fine..second..fine third fine...dropping gears lovely..

So I'm ecstatic that it looks like it was the battery but what could be the issue with 'drive'

Thanks guys

 

[V12]

If it completely cut out it sounds like you didn't tighten up the battery terminals.

 

[Chiefriley]

If it completely cut out it sounds like you didn't tighten up the battery terminals.

You were bang on...left pos untightened...

SO there we have it..anyone in the same boat CHECK THE BATTERY..I had my tranny fluid looked for no reason..was about to replace a wheel sensor..and all the time it just needed a battery.. I can even switch the ASC on and off too!! No reset nothing...

Thanks everyone and happy Xmas : )