Repeat Check Engine lights, P1235 & P0172 codes

[Chachacharlie]

All stock 2004 MM. No noticeable performance hit at all.

Got first light +/- 6 weeks ago. Codes were P0172 (lean indicator bank 2?) and P1235 (full pump driver circuit out of range). Reset, went a few days and came on again. Very trusted mechanic - Pikes Peak champ Clint Vahsholtz, total Ford guy - did full diagnoses with all the high tech gear. Nothing wrong. But just had fuel filter replaced with generic (along with thermostat and trans service with trans kit) a few weeks before.

He then consulted his own online sources and found these & similar codes sometimes triggered by non-Motorcraft filter. Pressure drop across filter just different enough. He replaced filter with Motorcraft, no charge, and Check Engine lights went away.

Until Monday, got one again. P1235. Showed reading of 8010 above normal max of 8000 (whatever those numbers mean...) Not really significant, Clint said.

Reset Check Engine light again; waiting for next time...

Any connection to this? Normally live and drive at 8500 feet. Every time, light only came on after driving down to Colorado Springs at 6000 feet.

Any suggestions would be much appreciated. Right now only solution seems to be to replace full pump assy. or fuel pump control module, or both. I don't want an important fault to be masked by this minor one. Not willing to drive around with Check Engine light on all the time.

[Turbov6Bryan]

Very common to receive a check engine light after every time you change the fuel filter. Just remove the code, twice, since you did the filter twice :)

Now that code have gone since last filter change,... drive it. Any codes pop back up?

Do you have a scan tool?

My experience on these cars is the pump starts cavitating and heats up and shuts off. I would say the driver is fine since the car runs and drives fine.

Be on the lookout for a rock auto fuel pump

[RF Overlord]

As Turbov6Bryan said, it's common to get that code after a fuel filter change, but normally it comes on right after you start the engine, or very shortly thereafter. Cycling the key on and off a couple of times before the first start keeps it from setting the CEL. Have your guy check the fuel pressure with his fancy machine...

[Chachacharlie]

Thank you for your replies.

Checked work orders: brand new generic fuel filter on 11/22, multiple CEL's & resets, replaced with brand new Motorcraft on 12/22. Advanced diagnostic gear hooked up to fuel system at that time; no problems indicated. No CEL from then until Monday, 1/30. Read P1235 and reset on Tuesday, 1/31. No CEL's since, but not much driving, either.

A few questions, if I may:

1) Can electronics "learn" over time that there really isn't a problem requiring a CEL? Or will being ever so slightly out of range make them pop up again & again?

2)Re. cycling the key: only after new filter, or after resetting CEL with scanner? And do you mean turning key forward almost, but not quite, to engine start? Any point in doing it now after driving for 2 days with multiple starts?

3) Don't own a scanner. Can you recommend one for "occasional home use" that's not too expensive?

4) Re. Rock Auto: they show several fuel pumps. Did you have a particular one in mind.? Would want at least OEM quality.

5) Isn't module the more likely suspect if this keeps happening?

Autocodes.com shows P1235 MERCURY - Fuel Pump Control Out of Range

"Possible causes:
Faulty Fuel Pump Drive Module (FPDM)
FPDM harness is open or shorted FPDM circuit poor electrical connection
Faulty Powertrain Control Module (PCM)"

"What does this mean?
The P1235 code indicates the Fuel Pump Drive Module (FPDM) detected an invalid or missing Fuel Pump (FP) circuit signal from the Powertrain Control Module (PCM). The FPDM sends a message to the PCM through the FPM circuit, indicating this failure was detected. The PCM sets the DTC when the message is received."

Thoughts?

Again, sincere thanks for any help & advice.