2005 O2 sensor codes sanity check.

[Scooterfitz]

I am no mechanic, but I know enough to be dangerous and I like to think of myself as a logical troubleshooter, so here is my issue and hypothesis and I am looking for confirmation that my thinking is correct…
I just purchased 2005 Expedition XLT with V8 5.4L V3 Triton – 150K miles. The day after purchasing the check engine light came on. Went to auto parts store and these are the codes and recommended action:

SUMMARY: Code P2197 indicates the PCM detected the bank 2 sensor 1 oxygen sensor failed to switch from lean to rich for a predetermined period of time during self-test.
P2197 O2 Sensor Signal Biased/Stuck Lean – Bank 2, Sensor 1 Stored
P0152 O2 Sensor Circuit High Voltage (Bank 2, Sensor 1) Stored
P2197 O2 Sensor Signal Biased/Stuck Lean – Bank 2, Sensor 1 Pending
P0152 O2 Sensor Circuit High Voltage (Bank 2, Sensor 1) Pending
P0059 H02S Heater Resistance (Bank 2, Sensor 1) Pending
RECOMMENDATION: Replace the positive crankcase ventilation (PCV) tube.
EXPLANATION: The crankcase breather hose is a component of the positive crankcase ventilation (PCV) valve system wihich vents excess pressure from inside the eengine. The breather hose is what allows crankcase gasses to be removed from the intake and burned off iin the cylinders.
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Sanity check 1: Their recommendation was to replace the positive crankcase ventilation (PCV) tube. After doing some research, these gasses would be be present on both exhausts. Logic makes me think if this was the issue, BOTH upstream O2 sensors would be showing issues. Correct?

As I researched, I found this thread: https://www.expeditionforum.com/threads/p0059-and-p2197-with-some-diagnostics.55712/
Sanity check 2: As all the faults are with one sensor, all at the same time, I think I should start with checking this connection as shown at the thread above?
Sanity check 3: If that does not do it, then the 02 sensor itself is probably the culprit, especially seeing as it has 3 errors on the same sensor, at the same time. Correct?
Sanity check 4: Finally, what is the chances it could be a fuel injector? Since these errors are all on one bank, is there a chance the sensor IS good, and a faulty fuel injector is in fact causing the stuck lean code? But it seems to me that would not cause a circuit high and heater resistance error, especially at the same time, so probably not a fuel injector, but just want to run my reasoning by others for, like a said, a sanity check.

Parting question… If I was to replace the O2 sensor, my auto parts store has a few in the $40-$90 price range; Walker, Bosche, NTK, and then the OEM Motorcraft one for $140. Should I get the Motorcraft one?

Thank you all!

 

[whtbronco]

Checking the integrity of the wires from connector to connector is a good place to start. Checking the integrity of the PCV tube and elbow(back of intake) is easy and free so may as well check that too. I do agree the PCV is not the likely cause of the O2 sensor issue though.

For the parts question. I have generally found that OEM parts to be the right answer. More of then than not they work and last longer. The premium price is the issue we tend to have with OEM parts. If it's an easy part to replace I'll take the chance sometimes. If I can identify the OEM part manufacturer I will sometimes by the part under their label. Such as the IAC valve that Hitachi made for Motorcraft, I go with the Hitachi for 2/3 of the price.

Go to https://charm.li and down the load service manual for your Expedition. The wiring diagrams and connector views will help tremendously in this troubleshooting adventure. Here's an example.



If by chance you find the O2 sensor is faulty, here's the Motorcraft upstream sensor. $62 plus shipping and tax:

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[Scooterfitz]

Everything checked out good for continuity. I bought a new O2 sensor, went with the Bosch, and crawled under it. when I went to remove the original O2 sensor, it was hand tight. It might have just been loose, but I swapped it out anyway and used an anti-seize on the threads. Took it out for a drive and it ran great. Made a couple of stops and by around 60 miles it cleared it's own CEL. My girlfriend and I gassed it back up and took it for a 320 mile ride trip through Summer Lake Hot Springs. We thew a futon mattress in the back and slept under the Oregon Dark Skies stars. Had a great trip. I really like this rig.

 

[Taekwondad40]

PNW, nothing like all the places we can go up here!