Code P2629 on my Ford Expedition 2013 EL XLT 2x4 - how to carry out the PCM self-check?

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pratik

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Hi all,

Since February I have been getting the DTC P2629, which used to come on monthly basis, but then every few days, and lately within a matter of days/hours/minutes. 2 weeks ago I tried replacing HO2S on pre-catalytic converter on driver side (Bank 2, Sensor 1), but that did not help, and neither did the CRC 05103 QD electronic cleaner.

Today (5/13/22) I got these 5 PENDING codes:

P2629 - O2 Sensor Positive Current Trim Circuit/Open Bank 2 Sensor 1
P0151 - O2 Circuit Low Voltage (Bank 2, Sensor 1) (possible causes - short to ground from any of the 4 wires)
P064E - Internal Control Module O2 Sensor Processor Performance - Bank 2 (it can be wiring or PCM.. if addressing other DTCs doesn't solve the prob, maybe it needs a new PCM!)
P1647 - Linear O2 Sensor Control Chip (Bank 2) (damaged wiring or damaged PCM)
P2197 - O2 Sensor Signal Biased/Stuck Lean - Bank 2, Sensor 1 (This DTC sets when the fuel control system no longer detects switching for a calibrated amount of time.)

I checked all the connections based on Pinpoint Test DZ (for P2629, and also P0151) and came to conclusion that there is no wiring issues / short circuit, and it is a PCM problem (per DZ15, the UO2SGREF circuit voltage came out to be 2.23 V, rather than 2.4-2.6 V, pointing to DZ28 - same for P2629 diagnosis, where DZ27 pointed to DZ28).

DZ28 asks to carry-out PCM self-check - how to do it? What are the next steps?

Thank you,
Pratik
 
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pratik

pratik

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Update 5/19/22:

I got a PCM from car-parts.com (Eastern Automotive, ~$150) and fit it to my Expi and have it programmed (Go Powertrain, $199). This resulted in somewhat smooth drive (or is it an illusion?) but engine light came on in a matter of minutes with code P0024 (Exhaust Camshaft Position Timing - Over-Advanced (Bank 2)), and won't go away, even after swapping the camshaft sensors (if it was camshaft sensor, I was expecting to see code P0014 - Bank 1) and topping up the oil by adding 1 quart, which brought the oil level from mid-way to top mark on the oil gauge. The dreaded P2629 code went away!

With the tight association between switching the PCM, appearance of the new code (P0024), and disappearance of the old code (P2629), I was convinced of two things:
1. The older PCM has either hardware or firmware issues. Assuming hardware issues, I got the newer PCM.
2. The newer PCM has hardware issues, as P0024 showed up after installing the latest firmware.

So, we replaced the older original PCM and flashed it with the latest firmware and now P0024 disappeared and after a day of driving the P2629 has not showed up so far. So, I am hoping that it was corrupted PCM firmware that was giving me the P2629 code and flashing the PCM solved the issue. The Pinpoint Test DZ suggested to replace PCM but I guess the assumption behind it is failed hardware (and not firmware). So, if one has access to flashing firmware (J2534 USB devices are available for <$150 on Amazon with good reviews, and Motorcraft subscription to Ford firmware is available for as low as ~$60 for the duration 2 days), one can try that before investing time and money and resources into PCM swap.

Thoughts?
 
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pratik

pratik

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Durham, NC
Update 6/10/22:

Tried another PCM from a junkyard, and that made my car drive little lethargic and the P0024 code came up! No P2629 code.

The original PCM does not show the code P0024. The car drives really awesome with the original PCM, except the on-and-off P2629.

What to do?

Thank you!
 

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