HELP JUST BOUGHT USED PRIVATE CAR Fault codes and check Engine light w205 c250 d

[Mercman2021]

Hi ,

I bought my first merc privately yesterday and after it driving it home for 2 hours the check Engine Manament light come on .

the car is a w205 c250 Diesel auto convertible, I bought it as a cat n repaired car , I paid £160 for a third party inspection that took the mechanic 2 hours to complete the only fought he found was the break pads are a little low he did mention some fualt codes but as the Engine management light was not on and the car drive excellent the mechanic said he was not concerned with the codes and that most cars would show some fault codes, he cleared the codes and we bought the car .

so this morning I borrowed a friends x100 ob2 reader it is a simple device and scanned to get these codes :


Po742: touqe converter clutch clutch circuit stuck on

U0121: lost communication with anti-lock braking system ABS control module


Pending codes trouble code 1
P2243: O2 sensor reference voltage circuit open bank one sensor one

I clear the codes and and the check Engine light goes off if I rescan with out driving no codes show up I take the car for a drive and rescan and the codes are back but at the moment no Engine management light is on after driving for ten mins

After clearing the codes the check engine light comes back on sometimes after driving for 2 hours other times after only 10 minutes of driving.

The gear box seems smooth the breaks feel fine at all times there is no abs lights or other warnings

apparently it was previously water damaged via the roof and this caused electrical problems hence the insurance writing it off , but this could just be a story as sometime people don’t want buyers to think there is a damage to the bodywork etc .

what’s the situation with these types of fault codes that do not kick the EML light straight away on and do not show any physical symptoms to correlate with the suggested faults?

 

[markjay]

The car will need to go on STAR, and possibly test-driven while the mechanic is checking live data.

Water damage can cause all sorts of intermittent electrical faults... sorry if this is not what you wanted to hear.

 

[Petrol Pete]

Hello and welcome .My concern is that having paid for an inspection the inspector basically ignored stored codes and he would only be concerned if an EML was actually illuminated ?

"...most cars show would show some fault codes .." is what the inspector told you. Unless he can tell what those codes meant I think you should ask for your £160 back.

As advised , I think you need to get it read by STAR.

 

[Mercman2021]

Thanks for the response.

I’m not entirely sure I believe that it has had previous water damage and not repairs to body work as the reason for writing the car off.

Any idea on what someone will charge to put it on STAR and test drive with live data if necessary?

As the car seems to be driving fine and from what I can tell nothing wrong with gear charges, idling, fuel-efficientcy

Would a a faulty o2 sensor cause loss of power , smoke etc ??and if the converter clutch circuit was stuck on as the code Suggest would the car not stall?

I’m not planing on taking it on any long trips until it is sorted but is it likely that driving with a fualty o2 sensor and the other problems could cuase further damage?


i am waiting for the mechanic to call back but not holding my breath

 

[Mercman2021]

Right I managed to confirm that it is the P2243: O2 sensor reference voltage circuit open bank one sensor , is the code that is kicking the Check engine light on .

this fault was confirmed on freeze frame and can happened at a random time had it happend when the rpm is at 1100 and doing 67km and when rpm is at 750 and doing 0km .

so where is this sensor located and what are the costs for replacing it ?

 

[Petrol Pete]

P2243 Mercedes-Benz Oxygen (O2) Sensor Reference Voltage Circuit / Open (Bank 1 – Sensor 1) – CarObdCode.Com

According to this it is the first one before the Catalyser. Cost ? I have no idea . If it's easy to get to and can be DIY'd then its just the cost of the sensor and new washer.

If it is a complete pig to get to and needs partial dismantling of the car and a special socket to get on to it ...and if it's seized in and the thread in the stub needs re tapping the cost will rise.

Someone on here will have changed one or can point you in the right direction, the last one I did was a piece of cake (Toyota) but some are not so easy.

 

[Tomhorton16]

I replaced the Nox sensors (next to the 02 sensors) on mine not too long ago, unfortunately Mercedes placement of these leave them vulnerable to water damage, or so the mechanic tells me. In terms of cost it was £1200 but the vast majority of that was the parts and I am in London so everything costs more, I wish you luck!

Side note: I really would get it sorted by Mercedes themselves, I took it to three different garages and they were all a bit puzzled

 

[E55BOF]

Have the job done by a good MB specialist, not a main dealer. The fault code tells you what needs doing. Tell us whereabouts in Kent you live and somebody will know of a suitable indie.

 

[Chrishazle]

You location is Kent - anywhere near Ashford? If so, head to Arrowfleet Maintenance (next door to Arrow Taxis) in Cobbs Wood Industrial Estate just off the A28 Ashford to tenterden road. They look after Arrow's fleet of MB's, mainly E class 220D's but also others, they have full genuine MB Star/Xentry and know their stuff. Their rates are also very competative, especially if paying cash. Have used them myself a few times now, so recommendation based on personal and recent experience.

If you're Maidstone way, https//www.stevensonsmercedeskent.co.uk always get good write-ups, not used them myself.

 

[pmcgsmurf]

OP not been back since June 27th folks.

 

[E55BOF]

Ooops...

 

[TeddyRuxpin]

Don’t mind saying it sounds like he bought a lemon then