faz492

Hey, i've come into a small issue,
I had my CEL come on, m156 amg ran too rich, changed the pre cat sensors which were causing the issue, I replaced both for 2 new ones.
Now the car is saying:
0563 - G3/3 (left o2 sensor before TWC (KAT)) : Open circuit (P2629).

Has anyone seen this problem before?
Could the wiring harness be melted from the exhaust or anything?
Could it be the new o2 is faulty?
could it be the wiring harness or the plug pin?
I hope someone has the answer for me..
Im really stuck in a rut with this e63 amg m156.

faz492

bump..

faz492

left exhaust pipe, blowing bit of smoke, running rich dumping a lot of fuel.
Got my new o2 sensor pre cat today, if anyone in the future have this issue i may narrow it down for you.
If its wiring harness issue will post that as well.

OmgNo_C63

Hey man,

Where you able to figure this out? I am having the same issue, changed the o2 sensors for new OEM ones and the code still came back on.

sunil517

They do have injector issues.. How many miles?
let it idle and if you are handy pull the plugs on that bank and look if one of them is really bad and that will be the injector with the issue. I would change all 8.

OmgNo_C63

Not that I am aware of (since no CEL related to injectors), will buy the tool to pull the plugs today as I dont have the right now.

More info on this issue here:

https://mbworld.org/forums/c63-c63s-...mg-2019-a.html

sunil517

Check to make sure non of the pins are pushed back into the connector on car harness and try to trace as much as possible looking for damage.If you had any work done try looking where they did that work for damage.
How many miles on the car might need plugs anyways.. before you change plugs if you do.. Clean the TB first and intake with old plugs on and swap our plugs if you decide to change them.