w124 potentiometer error

[rushikesh]

Having a problem with my mercedes benz E220 petrol W124 chasis - CO POTENTIOMETER R33 input short to positive ...... what possibly can It be ? is it anything to do with o2 sensor ??

 

[grober]

HFM Code 77 (CO potentiometer Input short to positive) - PeachParts Mercedes-Benz Forum
There are two possibilities one the MAF sensor on the inlet or two the lambda sensor on the exhaust- in either case the fault may not lie with the sensor itself but with the associated wiring loom. The MAF sensor is more likely to give driveability symptoms

 

[tjamesbo]

Wiring to the MAF on mine was degradedvirtually no insulation i was amazed the car still ran I renewed the wires over the hot part of the engine and all good now check the individual wires in the harness to the MAF

 

[rushikesh]

I did check all the wiring harness including the maf sensor.
Everythings gotta be fine.
I guess gotta need to check the o2 sensor on the exhaust.
moreover I got NO rough idle things on this engine but the check engine keeps on flashing