dennis10

Hi Chaps,

Please could you guide me in the right direction for things to check / sort out as a matter of course having purchased a CLK230 cabriolet

Are there things to easily check to make sure it's basically running right, ie MAF and other sensors? I basically want to make sure from the off that I have a good base, I usually service any cars I buy, but it's handy to know what are the usual culprits on this engine

I'm going to install scantool tonight on my laptop, already have an OBD2 cable from my previous cars - will this work ok with the W208, ie clear codes etc?

Thanks

cindyclk

my advice...if it ain't broke, don't fix it.
If the MAF is gone, it usually stalls, stutters, throws a bad O2 sensor code
if Stalls when hot...usually TPS
if get anti skid error...usually bad brake pedal switch
...there than that, they are usually bullet proof.

device2

I would have to say that it depends on the mileage too. Honestly out of the 3 luxury German cars we own, the CLK is truly very reliable and hardly ever needs any tending to besides the normal scheduled maintenance stuff like flushing the break fluid every 2 years. Changing the oil as needed, then the rest is as CindyClk said bulletproof.

A1EK

From my experience the enginese are strong, but the let down is the body work with rust however dependant where you are inthe world you may be okay and try ang get the last models after 2003.

Rust aside, if the MAF is good then you will know as the car will run smooth so leave it alone. If there is problem with the MAF then your car will run poor, slow acceleration, hesitant, fluctuating revs and the supercharger may stop working.
If you do need a new MAF then buy original new or second hand, DO NOT buy OEM they will fail. Check the condition of the MAF by undoing the clips at the rubber pipe, the MAF should be dry with no oil, if there is oil then this is an issue with the breather inlets on the fuel rail which is a DIY fix to clean out.

Use can use a cheap OBD2 scanner tool and download phone software like Torque and you can use it to check codes and clear them too. You may need an adaptor from the Mercedes round pin to the rectangle type but all in should only cost you about £5 for adaptor plug and £8 for the OBD2. (The socket may be in the engine bay by the way)

ABS and ETS lights on the dash can be due to a very common issue with a faulty brake light switch and is a cheap easy fix.

Otherwise just see how things go.

Good luck

dennis10

Thanks for the reply chaps.

I already have Torque Pro and an OBD2 bluetooth dongle that I've used successfully with a number of previous cars..

Have used on my CLK230 and originally I got these errors:

P0101 - Powertrain - mass or volume air flow circuit range/performance problem

P0420 - Powertrain - catalyst system efficiency below threshold (Bank 1)

P200B - powertrain
P201E - powertrain
P201D - powertrain
P200E - powertrain

I cleared the codes and ran again for a week, had the following pop up again:

P0101 - Powertrain - mass or volume air flow circuit range/performance problem

P0420 - Powertrain - catalyst system efficiency below threshold (Bank 1)

P200B - powertrain
P201E - powertrain

I am experiencing poor acceleration and hesitation (slow climb of rpm), when planting the throttle and sometimes it doesn't seem to want to change/kick down when being aggressive with the throttle.

It seems to be fine when just cruising around, although I do a mix of driving A&B roads and I'm only getting an average of 25mpg across the tank, which I don't think is that good

Where should I start? Worth cleaning the MAF or is it likely just goosed? Anything else I should look out for regarding the above codes? I checked the MAF and it's an original Siemens unit - so replace like for like?

Would a faulty MAF also cause an issue with cat sensors or is that a separate issue?

Many Thanks!

dennis10

One other thing to add - I seem to have a rattle/tapping sound when accelerating, it sounds alot like an exhaust manifold blow (so you can hear the lifters through the blow) which seems to be coming from underneath/rear of engine bay, but it's hard to work out because it's alot more obvious when driving

Would this be a common thing on the CLK230? And could it cause the above error code for bank 1 ie it sees too much air being drawn in?

A1EK

Have you tried unplugging the MAF and see if it improves the acceleration?
Could also be a blocked exhaust at usually at the CAT if its broken inside.

dennis10

I did try that on my way home yesterday - unplugged it and it did seem to run better - was still bad on fuel, averaged 25mpg, but pulled better and seemed to want to kick down when i wanted to.

It did throw up a load more codes, but this is to be expected if a sensor is unplugged I guess - have ordered some contact cleaner for now to see if the MAF is saveable, will check it for oil contamination.

How would I best troubleshoot the other issue with possible blow/rattle/tap?

A1EK

Its sounding like its the MAF then, unplugging it is a good way sometimes to determine if it is failing however you car will not have good mpg's running without etc.

Has the MAF sensor got oil on it? if it has then this relates to blocked breather nozzils on the fuel injection side (there is a seperate DIY for this, not too difficult).
You can try cleaning the MAF, but more than likely its gone, so get a new one. Word of advice though is buy original not OEM, if you cannot afford it then second hand original, OEM will fail its just a matter of time.