Just purchased a 2007 F150 crew cab 5.5 bed 4x4 with a 4.6 triton 210k miles that’s been well maintained. Recently had intake replaced, induction module replaced, 2 COP replaced in last 6 months, evap module replaced, and tank pressure sensor replaced. All the codes were gone after those repairs I’ve been told. Before purchasing the vehicle I scanned it and it showed 3 codes, P0308 misfire on cylinder 8 and P0135, P0155. I replaced the COP #8 and that code cleared out leaving the 2 other codes. I replaced all 4 02 sensors with Bosch direct replacement. Cleared the codes and they came back. I’ve checked all the wiring and can find no problems. There is 12 volts present at both upstream heaters. Both heaters are heating up. You can feel them heating with your hand and see them with a flir thermal scope. I’m getting varying voltage feedback from all 4 sensors between .1 and .9 volts. I’ve reset the KAM. I’ve unplugged every sensor on the same circuit with the 02 sensors and tried to clear the codes. I get the P0135,P0155 codes along with whatever other sensor I have unplugged. The only thing I can see missing is there is no amperage draw showing on my snap on edge scanner for the 4 heaters but I’ve been told the pcm probably doesn’t support that.
I’m stumped and everybody I know is somewhat stumped on this one.
Anyone run into something like this before ?
The truck runs fine besides a slightly rough idle and seems to get less than expected gas mileage on the first 1/3 tank.
Its not going into closed loop and I’m concerned about damaging the cats if this is left unsolved.
Any help would be greatly appreciated.
Thank You

This has been discussed, with mechanic friends outside ford dealerships and inside ford dealerships. While it is a thought, everybody kinda agrees if they are heating, and they are ohming out the same as OEM ford sensor heaters can that be the problem ? You would think if there were a issue with Bosch 02 sensors going in F150’s there would be some chatter about it on the internet but I can’t find any. That’s pretty much why I’m here asking, I’m down to throwing some decent money replacing parts at this point swapping out known good Bosch 02 sensors to ford 02 sensors or swapping the pcm out.

That’s what I was told, the only reason I went with the Bosch was the truck was off the ground and the dealership only had one in stock and my parts guy there told me Bosch made them for ford.

Ok, so just to rule it out, I went to the dealership and picked up a ford OEM front 02 sensor and put it in the drivers side position this morning. Cleared the codes out. Started the truck and approximately 5 seconds later I had P0135 & P0155 both back, while the truck was running I cleared the codes out and approximately 5 seconds later had both codes back. The exact same results as I had with the Bosch sensors in both sides, so I’m going to rule out the finicky truck only accepting OEM 02 sensors. The OEM heated O2 sensor is heating up the same as the Bosch is. They are both heating up, no fuse is blown. I’m stumped ?????

Relatively new Napa legend premium. It’s strong.

For giggles I just grabbed my ford battery analyzer and tested both CA and CCA and it tested 95 amps above it’s rated CA and 40 amps above it’s CCA so I’d say battery is OK. I left the ford OEM O2 sensor out of the exhaust hanging. I turned the ignition on, got on the creeper and rolled under the truck. By the time I got under the truck the tip of the O2 sensor was getting pretty hot.

I would think a short of any degree would pop fuse 32 which feeds several other items on the engine. If there were a break they would not have voltage at the 02 plugs. A digital VOM will show voltage when no amperage is present so there could be a weak connection but I’ve inspected every connection between the PCM and the O2, they all look good and I applied dielectric grease to be certain they were good. Plus the element is heating so it does have some degree of amperage to it. I’m getting feedback signals from all 4 O2 sensors. I’m curious if I should be seeing amperage draws on my scan tool from the 02 sensors. They are showing turned on but are showing 0 amps. I’ve been told they should draw 2 amps, but I’ve had a couple techs tell me they weren’t sure if my PCM supported the amperage draw reading. But I don’t know how the PCM decides if there is a fault with the O2 elements if it isn’t monitoring the amperage they are pulling or not pulling ?

That’s why I bought the only one the dealership had and installed it in the drivers side position. I got the exact same results, I was hoping I would only get 1 DTC for the passenger side but nothing changed. Same time for CEL to come on, same time for both DTC to come on, same feedback signals. Based on that I’d have trouble convincing myself the Bosch are the problem and replacing all 4 with ford OEM. My gut tells me it’s not the sensors but something common to them causing both codes. Another sensor, the PCM, something common to both ???

Its accepting the O2 sensor signals for rich, stolic and lean. Where my problem seems to be is the O2 heater circuit. The only DTC’s I’m getting are the P0135 & P0155.