2003 Chevy Express 3500 6.0 O2 Sensor

[HiccaBurp]

My '03 Express 3500 has codes P0134, P0154 & P0300. The first 2 are O2 sensor related. The P0300 is not specific and could be one of many things. I'll start with the O2 sensors.

The issue i'm having is determining which sensor and how many? Looking at the parts online, there are downstream, upstream, left bank, right bank, etc.. Is there a diagram showing all the O2 sensors? Looking at them online, some are specific to location, some O2's seem like they can go in either position?

 

[bluestream]

Upstream are before the cat, and downstream are after. The upstream are the important ones.

Always replace the upstream in pairs, or you can get a code

 

[Trav]

P0134, P0154 are O2 codes for the upstream sensor on bank 1 and bank 2.
The chances of both of these going out at the same time for no reason is highly unlikely.

These codes will cause a P0300. First things first , check the O2 heater fuse, it should have one. One bad O2 heater can kill the fuse that effects both of them (many cars).

Then check any common connectors these 2 share. There probably is one, i will look later at a diagram.
Put a proper scan tool on the job before throwing any parts at it.

I haven't looked or investigated, look in the manual for fuses, replace one if blown, if it blows again then you will need to diagnose which one is causing it.

Just some ideas for you to work with.

 

[SteveSRT8]

^^^Some good ones, too.

Many times when we see an o2 code it is a simple wiring issue, easily fixed. The fuse can and does blow but not very often...

 

[HiccaBurp]

Originally Posted By: Trav
P0134, P0154 are O2 codes for the upstream sensor on bank 1 and bank 2.
The chances of both of these going out at the same time for no reason is highly unlikely.

These codes will cause a P0300. First things first , check the O2 heater fuse, it should have one. One bad O2 heater can kill the fuse that effects both of them (many cars).

Then check any common connectors these 2 share. There probably is one, i will look later at a diagram.
Put a proper scan tool on the job before throwing any parts at it.

I haven't looked or investigated, look in the manual for fuses, replace one if blown, if it blows again then you will need to diagnose which one is causing it.

Just some ideas for you to work with.


Thanks to all the replies. As for both going out at the same time, not true. My check engine light came on last year intermittently. I checked the code and it was only P0134 back then. Last week I got a solid check engine light and checked both and got all 3 codes. I was going to replace the bad O2, but winter in N IL came too soon and it's been cold. The van won't fit in my garage(heated). Now that the weather is getting nicer, I'm ordering the parts and tools(O2 socket) and change them out asap.

Thanks for the fuse idea, I will check them out. However, when I reset the codes, the CEL stayed off till I got on the highway and came back on around 70 mph

 

[SteveSRT8]

Make sure and spray them thoroughly with penetrating lube a day or two before the work is planned!!!

 

[HiccaBurp]

Originally Posted By: SteveSRT8
Make sure and spray them thoroughly with penetrating lube a day or two before the work is planned!!!


Thanks Steve! I was planning on it.