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Discussion Starter #1
I scanned my 2000 Taurus Vulcan with ForScan. I found a code in the Power Control Module of P1233. I did a lot of searching both here and on the internet and found that the code means the Fuel Pump Driver Module has quit sending feedback to the PCM. This is needed to allow the PCM to ground and control the fuel pump pressure. I hear the fuel pump prime, and the car starts and runs with no drivability issues. I checked the under hood power distribution box for the fuel pump relay which seems fine. Next stop was the in the trunk fuel inertia switch, which was connected and not tripped. In this forum I found two posts from Jeff K stating he carries a known good junkyard FPDM in his trunk. In another thread the poster had fuel pressures in the mid to high 50 psi and chartmaker commented that those reading are too high and should bring attention to the module that controls the fuel pump. I found on the internet that the failure of the PCM is rare, much more likely the FPDM. I read the possible causes of this code, faulty PCM, faulty FPDM, wiring, harness, connections. After reading Jeff K as well as chartmaker's comments decided to change out the FPDM. I am not placing blame on anyone, Jeff K has been consistent and advises testing, diagnosis, rather than throwing parts at the problem. Not only that he always advises the purchase of quality parts. chartmaker obviously has an immense experience and collection of photos through the years.

I checked the condition of the wiring when replacing the FPDM, only about two inches protrudes from the black wiring conduit and it looked fine. I checked the wiring connector and it seemed OK, the new FPDM had the correct number of pins and none were bent or distorted. I am baffled by the car fuel pump priming and running OK. Obviously every component of the circuit must be OK to prime and run.

Get this, yesterday before I had replaced the FPDM the fuel pressure at the fuel rail key on, engine off was 59 psi. Once started it ran a consistent at idle on the driveway 59-60 psi which is too much. Pointed to FPDM. Secondly no feedback from the FPDM to the PCM, pointed to the FPDM.

Today I replaced the FPDM and though the fuel pressures seem more normal, key on engine off 51 psi, idle on driveway 42-45 psi remain baffled and frustrated as the P1233 keeps reappearing.

Frustrated because I do not want to replace PCM only as last resort. Any insight or suggestions?
 

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Maybe you need to ohm out the feedback wire to the PCM to the pump module. No expert here but the pressure is not checked by the module maybe it is actually the fuel pressure sensor. Not sure what the feedback signal from module actually is unless it is a relationship between the signal to the module and from the module to the pump. Also since there is a pressure sensor signal to the PCM the PCM is still controlling pressure from that.
 

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Maybe you need to ohm out the feedback wire to the PCM to the pump module. No expert here but the pressure is not checked by the module maybe it is actually the fuel pressure sensor. Not sure what the feedback signal from module actually is unless it is a relationship between the signal to the module and from the module to the pump. Also since there is a pressure sensor signal to the PCM the PCM is still controlling pressure from that.
Maybe or likely '00 is a one year only but returned in '02 and later. As '00 had COP while '01,'03 had coil pack. It is a comedy of what ever they decided to do when ever they at Ford decided.
-chart-
 

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Discussion Starter #6
Thank you for your responses and suggestions. I think I will begin with kekaye56's advice to clean and reconnect the grounds. I know from reading here these cars are sensitive to poor grounds as well as a weak battery. It is raining here so will try to check and clean grounds on Monday. I was looking at the diagrams posted by chartmaker. There is a wire from the FPDM that returns to the PCM and is titled diagnostic. I believe the PCM not seeing this return diagnostic is causing the P1233. From reading believe its function is to monitor fuel pulse modulation for duty cycles. Chart's logic about FPDM being in a relatively protected area compared to the F150 is appreciated. Not sure if it makes a difference but my 2000 Vulcan is a flex fuel vehicle and does have a coil pack. I believe my 2000 is a return less system as the fuel filter does not have the third connection. I would be thrilled if cleaning the grounds corrects my P1233. I am not certain I would have been aware of this code without ForScan. I am doubting problems with the PCM other than possibly the ground which has never been touched or cleaned in almost 20 years. chartmaker, thank you for your extensive photo documentation of your repairs.

Scott
 

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Discussion Starter #7
Reporting back on my PCM code P1233. I took kekaye56's advice to check the grounds. Thanks to Chart and others I knew where to find the PCM ground. I cleaned all the grounds including the PCM after sanding off the paint. The PCM did not appear too bad, maybe a little white fuzzys. I must admit to being skeptical this would solve my problem, most times the easy things don't go my way. After the battery was disconnected and grounds cleaned, I put it all back together and scanned for codes. The 1233 had been replaced with a P1000 which means the PCM cannot be scanned for codes until the IM monitors are online after the appropriate drive cycles. So until today have not known whether the code had been taken care of, or was still there. I am totally astounded and pleased that the P1233 is gone. Thanks to all, have read repeatedly these cars are sensitive to bad grounds and weak batteries. There are lot of good people and collective experience on this site.

Scott
 
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