CLS Amg 63

[alexanderfoti]

So that is saying the post catalyst fuel trim is too negative (rich).

This is not saying there is a problem with the o2 sensor.

It is saying the the system is trying to adjust trims on bank 2 and not achieving it. This is most likely on overrun condition. Check the air filters for blockage, fuel injectors for leakage etc.

 

[jon123]

So that is saying the post catalyst fuel trim is too negative (rich).

This is not saying there is a problem with the o2 sensor.

It is saying the the system is trying to adjust trims on bank 2 and not achieving it. This is most likely on overrun condition. Check the air filters for blockage, fuel injectors for leakage etc.

@alexanderfoti ok. So the mobilo report that says low voltage on the o2 sensor isn’t an issue with the sensor and is pointing to the suggestions you made?

 

[alexanderfoti]

Low voltage = rich

 

[jon123]

Low voltage = rich

Just one more thing to add (upon reflection) . It had a service done back in September last year and involved replacing the air filter, spark plugs etc. Would the air filter be blocked so soon ?

 

[SL63 Mark]

Just one more thing to add (upon reflection) . It had a service done back in September last year and involved replacing the air filter, spark plugs etc. Would the air filter be blocked so soon ?

No it shouldn't be, (unless you live in an exceptionally dusty environment, e.g. a desert or a quarry) but it is a five minute job to take the air filters out and check. It is easy to see whether they have been changed, new ones should be nice and clean.

 

[jon123]

No it shouldn't be, (unless you live in an exceptionally dusty environment, e.g. a desert or a quarry) but it is a five minute job to take the air filters out and check. It is easy to see whether they have been changed, new ones should be nice and clean.

@SL63 Mark dumb question time :

How do I check them ? Where are they located in the car ?

Thanks

 

[SL63 Mark]

@SL63 Mark dumb question time :

How do I check them ? Where are they located in the car ?

Thanks

Ah, it's the two big boxes on top of the engine. Remove the plastic engine covers first, by prising up (gently), unscrew the clamps on the air pipes, unplug the sensor and lift out the cleaner housing. There is one on each side, for each bank of cylinders. The housing clips in with two big clips. Mine is the 2016 M157, but I think it's the same as yours. Once you have the boxes removed, you can unscrew the lids and remove the filters to check they have been changed. Access to the screws is underneath, so you have to remove the entire housing.

This guy makes a bit of a meal of it, and doesn't quite finish the job, but you get the general idea.

YouTube M157 Air Filter Replacement


Hope that is helpful