does anybody know where exaclty the upstream o2 sensor is on the truck? mine went bad and need to replace it, does anybody know where it is and how i would remove it?

 

To remove it, the sensor should have a nut on it and screw out with a clip to take out the wires

 

ok..thanks..but where is it exactly?

 

upstream means its before the catalytic converter, on your exhaust. You need to find out if its bank 1 or bank 2 thats bad.

 

Very likely he has one before the cat and one after if he has the Federal emisions package. The California emisions package has two cats and a sensor before and after each.

The upstream sensor screws right into the exhaust pipe in a welded in bung just before the catalytic convertor and there is a wiring harness that will ned to be unpluged as well.When you locate it, you wil seeit is very easy and straight forward to remove. Be sure to disconnect the harness before trying to take the senosr out.

I replaced mine a couple weeks ago.

 

im pretty sure i have 2 cats. i have one after the headers...that larger tubebox thing, im pretty sure thats the first cat. then it goes to tubing and back to another cat, then some more tubing, then the muffler then some more tubing to the tip. ya. my truck runs like complete crap right now and believe its the o2 sensor and my engine code is P0051

 

P0051 is: Upstream Oxygen Sensor (right cylinder bank), heater circuit low voltage.

 

You really should say what year and what engine to make it easier to obtain help.

All of our trucks have o2 sensors before and after the cats, not just CA.

Since the code is sensor 2/1, that means that it is the sensor in front of the cat (towards the engine) on the passenger side.

There is a clip you need to disconnect for the wires. Then you will need a box (not open end) wrench to remove it. You may have to cut off the connector to the wrench over the connector. There are box wrenches that have a slot in them (line wrenches) so that you dont' have to remove the connector.

The sensor is on the exhaust pipe just in front of the cat on the passenger side.

 

sorry. its an 02 4.7. ok thanks for the help..but you say its the before the first cat, like 1 foot away from the engine, or in front of the second cat, near the muffler?

 

ok nevermind im sorry. scratch what i just said, i just went and looked under the truck. its in front of the cat, near the headers on the passenger side. thanks a lot for the help. hopefully i can replace it tomorrow bc it runs like **** and pisses me off