[Dan P]

1999 ML320

:surrender:

So my O2 sensors have gone bad and I've purchased new Bosch ones (the ones with the clip not the BS universal ones).

I'm having trouble disconnecting the clip that attaches the sensor wires to the car wires. Has anyone done this and can offer me advice. I'm looking for a tab or something to push to unlock the two pieces but can't get it to do anything. The car side of the clip has two protruding pieces with holes in each of them that clip on to two little bumps on the sensor side of the clip. I don't know how to lift up the protruding pieces so I can slide them over the little bump. Lying on my back and trying to squeeze my hands between the exhaust and other junk under there isn't helping.

And while I have you here, does anyone know where the knock sensors are located on these vehicles? I've got to do those as well.

Thanks in advance. Please leave any ideas, I'll provide pictures if needed!

 

[drewbush]

On the O2 sensors, grab hold and yank, not to hard like you are trying to tear it out of the vehicle. Hold the body side of the connector, apply some tension to the O2 sensor side and give a quick pull.

Why do you need to replace the knock sensors? Did you get codes? You might want to start with the O2 sensors first, and then see if your problem goes away. If a vehicle is idleing poorly due to poor mixture, it can cause the knock sensors to detect that as predetination.

 

[drewbush]

Oh and watch out for those heat shields, they can be sharp has a knife.

 

[Dan P]

Thanks for the response. I am starting with the oxygen sensors and hoping that will take care of it, I had codes for both knock and oxygen sensors.

I've also noticed the heat shields, they are pretty sharp.

 

[Dan P]

Success!

You were right, it just comes out with a bit of force. I was trying to use my fingertips and I just couldn't get it in that awkward position under the car, it's easier if you get part of your hand on there, heh.

As far as the result, the car runs noticeably better, throttle response seems better and it just seems to pull harder and smoother. Check engine light is off, but I did disconnect the battery. I'll take it on a trip and see if it stays off later today. Hopefully the knock sensors can stay in there, even though I've got two new ones sitting around now, because I have absolutely no clue where they are in the car!