Hello all, for a 1991 300SE M103.
I had a fault code 17 Check Engine light on and new Oxygen sensors had been replaced two times in a week and now still won’t fix.
After new senor drove it in around every 15 miles up hill of 118FWY Check engine light on with code 17 and Regular road driving Check Engine light is never on.

I know code 17 called for Oxygen sensor short to ground or wire short to ground. But how can I test it or fix it?

Any brains storm for this any one? Please help…..thanks in advance.


FYI… Recently new plugs (none resistor), cap, rotor, fuel pump, filters, accumulator, Engine temp. Sensor (a 4 pins one), belt, hose water pump, NO vacuum leak and smog check pass, and the car is about 170k miles.