andyy

Time for some updates.

In my case, the P0191 error code happened again about 2-3 months after I changed a new fuel filter. This time I have my fuel pump changed. Thank God that my fuel pump wasn't fixed within the fuel tank and can be changed alone. Now I had my fuel pump changed for about 1 month and currently everything is fine.

Doctodd33

bringing this back up......CEL came on with same codes.....0191 and 3699......the fuel pump was just changed prior to me buying it so now will try to track down the cause. Car is running fine.

andyy

Personally I also had the code0191 popped up again about 1-2 years after I changed the fuel pump for the first time.
The second fuel pump change also worked, however after less than 2 years the code0191 showed up even again!

That's when I suspected there might be some deposit or contamination in my fuel tank or fuel system.
Instead of change a fuel pump again which is quite expensive, I simply added some fuel system cleaner/fuel injector cleaner into the tank right before refuel when the tank is almost empty,
and magically the P0191 didn't show up again after I simply erased the error code with my iPhone and OBD2 adaptor.

Hope this also works on your car!

Doctodd33

Wondering how some type of contamination can cause high fuel pressure because that’s what the error code says. But yeah I’ll try that...easy enough.

PJK

I had the same thing happen to my CLK63BS this past spring, and I did the same thing (couple of bottles of fuel system cleaner). The code went away and hasn't come back (and I'm still on the original fuel pumps with 93k'ish miles).

Doctodd33

Thx.....which fuel cleaner is recommended nowadays or did you use? Brought it in today.

JPMD

Is also be interested to know the name/brand of the fuel cleaner/additive.

Good luck with the car.
please keep us posted on what the dealer finds.

andyy

Personally I used Autoprofi Petrol System Clean and Chevron Techron, both worked fine on my car.
Of course I think Keropur from Mercedes themselves is a good choice too.

JPMD

Ty

Doctodd33

they just called and want to change the fuel pump again under warranty with no charge to me. Verbally he said it was a high voltage from the fuel pump which doesnt match the codes the other shop found. The advisor couldnt explain it very well so he kept saying the shop foreman was qualified with AMG cars and that is what he said. Ill be going by in person. Im skeptical.

Doctodd33

I just went by spoke with the tech himself. He says that it’s an amperage error where the fuel pump needs more power because the fuel pump is bad. He thinks that these parts are old because they’re not used very often so it’s just a repetitive error that he has seen frequently. So this part of the diagnostic work up is to get a new fuel pump and see if it will fail on demand.

PJK

I've used Chevron Techron (not that is is necessarily better than anything else).

We'll see what happens in the spring. I wouldn't be surprised if I eventually have to replace the fuel pump(s), but it definitely cleared up the issue for the last several months.

Doctodd33

So they changed the fuel pump for no cost because there’s two year warranty on parts and labor on the parts, and I took the car home today. And the check engine light came on on the way home. Chevron Techron is next

JPMD

Holy crap. Thanks for the update. Please keep us posted and fingers crossed. Will be amazing if the Techron clears the code.

No CEL (yet) on mine but after recently joining this thread I put in Chevron Techron last time I filled up. I'm 1/2 way through the tank and will add a 2nd Techron next time I fill up.

Derekm15

How were you able to get warranty on the car? I looked everywhere before purchasing a car, only available was for veterans or current staff.

I've used Lucas Oil in my e30 but never anything in the CLKBS.

Good luck.

Doctodd33

The fuel pump was just changed in September. My dealership told me there’s a two year warranty on parts and labor installing those parts. There was no warranty on the car itself.

Doctodd33

Couple weeks ago I put some Chevron techron in the tank right before a fill up, and then drove to the keys and back almost using the entire tank. CEL was still on as of yesterday. Drove it today with 1/4 tank left and the CEL is no longer on. Car feels a bit peppier too.

Derekm15

the keys ? Are you in florida?

Thanks for the update.

Doctodd33

yes im in miami....it was a 200 mile drive that day

Derekm15

I’m in Miami half of the year and in la the other half. My BS lives in La I do wish it was in Miami at times.

The keys is a great drive with never much cars on the road.

AKnight55

Replaced the fuel filter ($750 parts and labor) cel gone and it seems to pull much stronger. I’m at 91k miles so it was due.

andyy

Hi,

So far as I know, the CLKBS fuel filter is integrated into the fuel pump, which doesn't have an independent part number and can't be solely acquired.
The link is the fuel filter/pump of another M156 vehicle, which is identical to my own fuel pump/filter on my CLKBS.

$750 is somehow too expensive for only a filter so I suppose you might changed the fuel pump as well?
Also if anyone know how to get the filter alone I'm very interested to know.

Doctodd33

thats what I was told as well by independent and mb service

andyy

On the video start from 1:10, we can see the filter part is still detachable and changable.
IMHO if we can manage to find a filter of the exact same size, we can change it with a much lower price compared with the fuel pump assembly.

AKnight55