Manual ML270 limp mode

[Warmy]

I have a manual 2005 ML270 which has gone into limp mode and not for the 1st time lol. Usual codes MAF EGR Inlet shut off boost pressure etc. 1st time this happened it was a short in the PCV heater wire which blew the hidden10A fuse, 2nd time was swirl flap motor jam, at this point I removed the inlet manifold disconnected the broken linkage removed swirl flaps and blanked them, as the motor still worked I just plugged it back in and reassembled and again replaced the hidden blown 10A fuse. All good for just over a year. I’m now on my way over to MOT the car, come to a set of traffic lights and here a pop from the front passenger side sounded like it might have been in the fuse box or near that area but hard to know, then smell of electrical burning, stopped and looked under the bonnet but couldn’t see anything obvious, so drove on over to MOT centre, car now in limp mode no Revs past 3000, no lights on dash, car past mot but still in limp mode. My immediate thought was M55 inlet shut off motor and on inspection I could see that the plastic cover was not present leaving the gearing exposed, so automatically thought that’s it, tried to remove the electrical plug from the M55 motor but could not, so cut the wire and using a chocbloc and 4.7k ohm resister connected to the red & green wires (taped the brown wire up out of the way) I’m not great with electrics, will this work? Anyway still in limp mode checked all fuses inc. hidden 10A at back of fuse box and all are good. Have vacuum tested EGR and it is good, removed the plug from MAF but still no revs over 3000. (If the MAF is unplugged will I get more revs?)
I now think my radiator cooling fan motor may have blown and this was the burning smell, I have tried to get the fan to kick in but it won’t could this send my car into limp mode with all the fault codes?

So my questions are

Will connecting the M55 motor cable to a 4.7k ohm resistor via chocblock be ok? and will the fault codes need reset?

With MAF disconnected can I tell if it’s to blame for limp mode?

Will a non working cooling fan put my car into limp mode with all the faults listed?

My memory of previous limp mode experiences were that once you fixed the problem the codes cleared themselves, is this correct or Will the faults need cleared and is there a way of doing this without Star?
can the codes even be cleared if there’s still a fault?

Any help or guidance would be greatly appreciated
Thanks in anticipation of your help

 

[mattkh]

faults need cleared and is there a way of doing this without Star?

Yes. For about £15, you can get a code reader that will read the codes via the OBD2 socket. It can also clear the codes.

 

[mattkh]

can the codes even be cleared if there’s still a fault?

Yes. What you do is clear the code, then use the car. If the fault is still there, then the error code will be recorded again.