- On KOEO, I'm pulling a P1747 consistently with a PCM that won't start the truck.
- I don't think it's the tranny. Truck drives fine with a different PCM.
- One of the DTC laundry list of possibilities (other than EPC Solenoid Short Circuit) is that the "PCM is shorted to ground."
? - In what ways can a PCM be shorted to ground?
? - Is there a pin point test for P1747? I can't seem to find one?
- In the past, the P1747 was accompanied by P1668 or P1670 (IDM electronic feedback) or P1249.
- Always passes injector buzz test, still won't start.
- With different PCM, starts right up.
- Can't perform other tests because won't start with PCM that has P1747 code
- Cleared all codes in between each test/retrieval.
- On a hunch, unplugged APCM, and it started and ran for 5 minutes. Shut itself off.
- Checked for codes. None. Ran KOEO. No codes, not even 1747.
- Tried to restart, still with APCM unplugged. No start.
- Behaves like I imagine a bad CMP might behave? But CMP works fine with different PCM.
? - Can different calibrations respond differently to the black versus the grey CMP?
? - Amplified question: is it possible that older original tear tags (as manufactured) may work fine with the original black CMP with gold bracket, but when those original calibrations got reflashed with updates by Ford during routine services, suddenly the original CMP became unreliable and eventually was recalled? Hence the grey CMP works better with the more recent, latest, and last calibrations? (This is a question, not a statement).
? - Could that explain why some people never had a problem with the original CMP, while other's did? The ones that didn't (me) never had a reflash on their PCM? (My working PCM has never been reflashed... my non working PCM has the latest reflash of the same calibration for my truck).
? - If any of the foregoing is possible, why no CMP codes, and only 1747, and now, as of this edit, zero codes, but still no start?
- I don't think it's the tranny. Truck drives fine with a different PCM.
- One of the DTC laundry list of possibilities (other than EPC Solenoid Short Circuit) is that the "PCM is shorted to ground."
? - In what ways can a PCM be shorted to ground?
? - Is there a pin point test for P1747? I can't seem to find one?
- In the past, the P1747 was accompanied by P1668 or P1670 (IDM electronic feedback) or P1249.
- Always passes injector buzz test, still won't start.
- With different PCM, starts right up.
- Can't perform other tests because won't start with PCM that has P1747 code
- Cleared all codes in between each test/retrieval.
- On a hunch, unplugged APCM, and it started and ran for 5 minutes. Shut itself off.
- Checked for codes. None. Ran KOEO. No codes, not even 1747.
- Tried to restart, still with APCM unplugged. No start.
- Behaves like I imagine a bad CMP might behave? But CMP works fine with different PCM.
? - Can different calibrations respond differently to the black versus the grey CMP?
? - Amplified question: is it possible that older original tear tags (as manufactured) may work fine with the original black CMP with gold bracket, but when those original calibrations got reflashed with updates by Ford during routine services, suddenly the original CMP became unreliable and eventually was recalled? Hence the grey CMP works better with the more recent, latest, and last calibrations? (This is a question, not a statement).
? - Could that explain why some people never had a problem with the original CMP, while other's did? The ones that didn't (me) never had a reflash on their PCM? (My working PCM has never been reflashed... my non working PCM has the latest reflash of the same calibration for my truck).
? - If any of the foregoing is possible, why no CMP codes, and only 1747, and now, as of this edit, zero codes, but still no start?