2000 Yukon Denali - Oxygen Sensor

Check Engine light came on -- was told it was a oxygen sensor. Changed the oxygen sensor, but light is still on. How do I reset this light. Thanks

May not be the problem get the code and post back, not all 02 codes mean to replace it. Plus there at least 3 on this truck. Kinda short on the info here.

Took this vehicle to shop and according to the code, this is the sensor I was told to change . . . but I do not know how to reset the check engine light.

If the problem was corrected the lite will go off by itself or can be cleared with a with a scanner.

I replaced both sensor 2s on both banks of my GF's Denali when she got check engine light at 101K. The codes read O2 sensor, bank1 sensor 2, and bank 2 sensor 2. I replaced them with direct fit Bosch sensors and cleared the codes. The CEL came back on and has stayed on. It is saying heater circuit for one of the sensors, maybe both. I don't have the truck in my shop right now. what do I have to do to fix this heater circuit issue? She wants me to just replace the sensors, but she doesn't understand that this issues is not likely the sensors. They are under warranty and I will replace them when I know how to fix the whole problem. any ideas? Sorry for the patchy info, when I get it on the scan tool again, I post the exact codes.
BTW it's a 2002 Yukon XL denali with AWD and a 6.0.

Welcome to AF. The heater circuits are fused for those sensors first thing to check ,also the wiring to the connectors along the frame rail often corrode or the ground side of the sensor heater is bad, again wiring diagrams and shop manuals are important here for a proper repair/diagnosis. BTW in the future start a new thread this is not really a continuation of this one, thanks.

Thanks for the help! Sorry for the thread hijack, I just figured it was the same topic. Any I will use this info and start a new thread with results. I will probably go with Alldata for the tech info.

Hey Max, thanks for being such a faithful Yukon contributor. It is much appreciated by so many that read these boards but may not post so much. WD

Max-I have codes
PO 174, System to lean
PO 101, Flow Circuit Range?performance problem
PO 171 System to lean
PO 1516
Could these codes send my Yukon 2003 5.3 engine into Reduce Engine Power?

Are the sensors hard to replace? Thanks in advance for your help.

Hey Max, thaks for the info you passed along to me. I found the blown fuse on the heater circuit, and acouple of days later the check engine light went out. You rock!

Max-I have codes
PO 174, System to lean
PO 101, Flow Circuit Range?performance problem
PO 171 System to lean
PO 1516
Could these codes send my Yukon 2003 5.3 engine into Reduce Engine Power?

Are the sensors hard to replace? Thanks in advance for your help.


Yes, a system lean code is your computer telling you that it's not getting enough fuel. As for the sensors, if you are asking about the oxygen sensors, no, they are not hard to get to, but make sure that's what your truck actually needs, you can't return them if you install them. You will also want to use the proper socket for removing the oxygen sensor. It's very similar to a fitting wrence. You can rent them at autozone if you don't have one. You will need it, open end wrenches can slip off and strip the sensor. They get stuck in there pretty good from the heat.

From the codes you have listed I would not go straight to the oxygen sensors. I'd start by checking fuel pressure.

Fuel pressure, What are you suggesting it may be? Also where is the bank 1 o2 sensor located

Are you getting an O2 sensor code, Or just the lean codes?
Bank 1 is the driver side, sensor 2 is the sensor in next to the cat. This should be under your floor, not on the exhaust manifold.
If you are getting lean code without O2 sensor codes, you could have low fuel pressure. Which can be fuel filter, fuel pump, fuel pressure regulator, injector issues, etc. If you are getting O2 sensor codes then the sensor could be the heart of the problem. How many miles are on the vehicle? Usually sensor two on both banks should be replaced at or near 100K. If you are at that mileage and you're getting codes for the O2 sensors, then I'd lean towards replacing them.

Had the same codes on my 01 yukon xl turned out to be fuel filter new filter. I cleared the codes all better

I had the same issue, I recently had my fuel pump go out and had it replaced. Shortly after that i noticed that it still surged a little and my service engine soon light came on. I took it back to the repair shop and had them replace the fuel filter and check the code. When he pulled it up it said o2 sensor 1 bank 1. He reset the light as i told him i would replace it and now the light is back on after the next cold startup. Can the o2 sensor cause the little surging that i get and if so, is sensor 1 bank 1 located on the drivers side nearest to the engine. Any help would be greatly appreciated.

What was the code, and yes sensor 1/1 is closest to the engine drivers side pipe.