C250 questions.

[Mario6806]

Hi Guys, I am new to this forum. Greetings to all.


I have a C250 W205 Dec 2014 that suffers from a random jerky transmission, initially, I thought it was the transmission itself but now I am thinking more of a misfiring engine due to old spark plugs, the car has 80K, I took the car to a dealer and as they found no saved codes, they only recommended a transmission service, which I did and paid $800 (expensive), and the car still jerks the same. This problem arises at low speeds, say 40 to 50, when you accelerate the engine downshifts from 4 to 5 and you feel like a hard shift, and I mean "hard" to the point that my passengers get scared, but this happens randomly. They also recommended an adaptation service where 2 technicians jump in the car with a laptop and check the gear changes on the car, obviously for this service is another $600 dollars and they do "adapt" the transmission, I don't know if this is true or not.

At the moment I am trying to work out the main issue with my car and see if I can fix it myself by performing services that and an average DIYer can do; like changing plugs, oil, etc.

So I would appreciate it if someone could reply to my questions

1. Has anyone experienced jerk or hard shifts when accelerating? How did you get it fixed?

2 . Also, just wanted to know if the issues on the M274 engine in the US ( W205 - I guess is the same here, correct?) are also present here in Australia? I am talking about "wrist pin" noises that lead to piston cracks if left unattended. - I have been reading that lots of C300 suffered from these issues in the US, is this issue also found here in Oz?

I don't have a C300 but I do own a C250 here in Perth, I am just concerned that this may happen to my car as it has a weird noise in the morning for about 2 min then it cuts off completely. I will post this tomorrow if that's ok.

[Ivanerrol]

It could be something simple as the Crank position sensor.
On the other hand - an adaptive test at $600.00 could turn out to be an adaptor plate problem with the cost in the $1000's

No codes will show.

[Ivanerrol]

Also

Make sure your battery is up to scratch. Correct voltage and residual capacity. Should be specified AGM of correct AH and crank capacity.
If it's more than 4 years old then it might not be up to doing the job. Lots of small trips means the battery doesn't get charged to full capacity.
Get the battery checked for residual life and the alternator charging correct.

It's essential that the correct fluids and filters are used and the correct level. A stealership shouldn't have any question of doing the wrong thing.
Fluid change every 60,000 Ks without fail. More often if a lot of stop start driving.

Plugs should last 100K Km's.
Transmission fluid change is actually a DIY job. Buying the correct tools to do the job is way cheaper than an $800.00 stealer charge.

[Mario6806]

Thanks, Ivanerrol for your input. I was going to do the transmission service myself but I chicken out because I didn't have a way of measuring the correct temperature of the transmission fluid as shown of some youtube videos and was afraid of leaving oil in the torque converter, so went ahead and pay for the service. Engine Oil and the rest of the fluids I do it myself. Yes the car is a 2015 model and I don't think the battery has been changed, I don't have a way of knowing.

Are the batteries on these cars DIY? ie Can I buy it from Repco or Supercheap shops? or does it need to OEM? and are they straightforward to replace?

[Ivanerrol]

Battery is DIY swap.
I bought proper Varta's from Every Battery
Changed the batteries in my W213 and W212 recently - no issues.
I tried using a memory keeper tool via the OBD port but it all did was blow the port fuse.
Didn't lose any program on both cars. - There's an auxiliary battery - make sure yours is OK.

get your self a scan tool.
Make sure it works OK with the W205. I have a iCarsort MBII and it doesn't work on my W213.

You can buy your self a cheap battery check tool of Fleabay. You can also buy a laser temp thermometer tool.

[Bartman4800]

Thanks, Ivanerrol for your input. I was going to do the transmission service myself but I chicken out because I didn't have a way of measuring the correct temperature of the transmission fluid as shown of some youtube videos and was afraid of leaving oil in the torque converter, so went ahead and pay for the service. Engine Oil and the rest of the fluids I do it myself. Yes the car is a 2015 model and I don't think the battery has been changed, I don't have a way of knowing.

Are the batteries on these cars DIY? ie Can I buy it from Repco or Supercheap shops? or does it need to OEM? and are they straightforward to replace?

There is a battery wholesaler for Bosch and other brands in Cockburn. They are significantly cheaper than all the car stores.

https://www.goodchild.com.au/

For your car, it came up with the following spec:

MERCEDES BENZ C250 2011 ON N88H AGM 60038/LN5 H3 (VT) / 9A49 / AGM90L 1

Regards, Bart

[Mario6806]

Thank you, Bartman and Ivanerol for your replies. It's good to know there are people out there willing to help others. cheers!

[John Green]

I have a C250 W205 Dec 2014 that suffers from a random jerky transmission, the car still jerks the same. This problem arises at low speeds, say 40 to 50, when you accelerate the engine downshifts from 4 to 5 and you feel like a hard shift, and I mean "hard" to the point that my passengers get scared, but this happens randomly. They also recommended an adaptation service where 2 technicians jump in the car with a laptop and check the gear changes on the car, obviously for this service is another $600 dollars and they do "adapt" the transmission, I don't know if this is true or not.

Spark plugs will not be the issue. When you describe the shift as harsh, is it delayed and harsh or shifting at the right time and harsh. Also what happens if you put it in sports mode and drive it using the shift buttons on the steering wheel. Same shaft point and harshness?

[Mario6806]

I have been trying to diagnose the issue and actually, the harsh or jerky motion does NOT happen when shifting, its does happen at revs around 3000 and while cruising and not all the time; this happens while driving at a normal speed. For example, I am doing 60 km/h (38 miles/h) and the car is sitting on D4 suddenly I get this harsh hit on the engine like a misfire and again it happens just randomly and not every day. That's why I am going to change the plugs soon and see if that helps.

[John Green]

I have been trying to diagnose the issue and actually, the harsh or jerky motion does NOT happen when shifting, its does happen at revs around 3000 and while cruising and not all the time; this happens while driving at a normal speed. For example, I am doing 60 km/h (38 miles/h) and the car is sitting on D4 suddenly I get this harsh hit on the engine like a misfire and again it happens just randomly and not every day. That's why I am going to change the plugs soon and see if that helps.

Hmm, OK. Even with that description it can still be the transmission. They can have issues with the various speed sensors not reading correctly, this will cause jerkyness as the transmission gets all confused. It thinks it should change, but then realised it shouldn't change, etc.

That said changing the plugs won't hurt.

[Mario6806]

well I did change the plugs myself and the car had a big improvement, no more sudden jerks when accelerating, only one on occasion; I was going down a hill and I almost missed the street I was meant to turn into; as I was doing around 80km/h I braked heavily and turned sharply into the street, I guess I went from D6/ D7 down to D2, as I accelerated I felt that bang/jerk/ or hesitance, and since then I haven't suffered any more issues. I would say that definitely, the issue was electrical and not due to the transmission itself but I am suspecting a coil could be still playing up.

[Mario6806]

I thought I posted a video I made regarding this issue, car violently jerking under acceleration. Well I fixed the car by swapping the crankshaft position sensor. Hope everyone find this useful.

https://www.youtube.com/watch?v=Z5BRganMolU&t=10s