Having benefitted from some months of lurking on this site, I thought I would share something that worked for me:
2004 Yukon 4.8 to 6.0 swap.
For the swap, I kept the original harness, and original pcm. Every few startups, I'd get P0135 and P0155 codes for the front O2 sensor heater circuits.
I had a friend write an hptuners repository tune (from a 2004 yukon xl 6.0). Same thing. Then segment swapped only the necessary segments. Same thing.
What seems to have fixed the problem is to use the trapezoid plugged O2 sensors (in the front only) from the 6.0 equipped GMT800s of these years.
The 2004 yukon 4.8 has square plug O2 sensors.
I bought some extensions on ebay (for Camaros getting headers), cut and spliced them to the old O2 sensor plugs. That way I didn't have to modify the vehicle's harness (or the sensors). The plugs have letters marked on them (faintly). A:A, B:B C:E D
)
Of course, you'll want to verify these pinouts for your own specific model (don't fry your pcm following my advice!).
Part # for the denso sensors I used: 234-4669
I'm posting this because I tried a lot of different things to solve this problem, and hours of searching the forums turned up very little useful advice on the specific issue I was having. Hope it's helpful for someone!
2004 Yukon 4.8 to 6.0 swap.
For the swap, I kept the original harness, and original pcm. Every few startups, I'd get P0135 and P0155 codes for the front O2 sensor heater circuits.
I had a friend write an hptuners repository tune (from a 2004 yukon xl 6.0). Same thing. Then segment swapped only the necessary segments. Same thing.
What seems to have fixed the problem is to use the trapezoid plugged O2 sensors (in the front only) from the 6.0 equipped GMT800s of these years.
The 2004 yukon 4.8 has square plug O2 sensors.
I bought some extensions on ebay (for Camaros getting headers), cut and spliced them to the old O2 sensor plugs. That way I didn't have to modify the vehicle's harness (or the sensors). The plugs have letters marked on them (faintly). A:A, B:B C:E D
)Of course, you'll want to verify these pinouts for your own specific model (don't fry your pcm following my advice!).
Part # for the denso sensors I used: 234-4669
I'm posting this because I tried a lot of different things to solve this problem, and hours of searching the forums turned up very little useful advice on the specific issue I was having. Hope it's helpful for someone!
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