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O2 Sensors stuck lean

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Joined: Mon Sep 09, 2019 2:06 pm

O2 Sensors stuck lean

Post by Formage » Mon Sep 09, 2019 2:13 pm

About a month ago I had 2 coil packs fail on my 2008 Ford Taurus X.
Unfortunately I also had to have the PCM repaired. After the initial repair I was still having issues and ended up having the company source a new board for me. Sent them the original one back so they could transfer the security information and got the 2nd one.
I replaced all the coil packs and spark plugs before putting the board back in the first time.
Now I have a p2195 and p2197 code that come in after about 1-2 minutes of idling. The FF data on my OBD2 reader shows 0V on either sensor.
These codes didn't come in on the first board before or after the repair, but came in on this different one. The company says they tested it before sending it back to me and had no problems. To me this seems to be a PCM issue still as the likelihood of both sensors failing at the exact same time seems very unlikely.
Idling doesn't seem to be rough and theres no lack of power when driving.
Any help or insight is appreciated.

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Re: O2 Sensors stuck lean

Post by spy1309 » Mon Sep 09, 2019 4:27 pm

That is a first here on the forum so we can t help that much......looks like the PCM , you shouldve tried a used one from a salvage yard , most of them are good than try a refurbished one.

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Re: O2 Sensors stuck lean

Post by EXPENDABLE » Sun Sep 15, 2019 3:46 pm

I also need similar help. I think my PCM may need reflashing but im not sure. All I know is Im reading lean on both banks with codes p0171 and p0174. I have literally spent over a thousand dollars replacing EVERYTHING related to emission.....
1. fuel pump
2. fuel injectors
3. fuel rail pressure sensor/regulator
4. fuel filter
5. mass airflow sensor
6. air filter
7. throttle body
8. egr valve
9. EVAP canister valve
10. upper and lower intake gaskets and throttle body gasket
11. all 4 o2 sensors

After I reset the computer it runs fine for about an hour. then after a couple cycles it starts acting up and hesitating like crazy and throwing those two lean codes from hell! any help would be appreciated!

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Re: O2 Sensors stuck lean

Post by Webmaster » Sun Sep 15, 2019 4:02 pm

Stop replacing parts, do a smoke test next.

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