03 MM PCM Wiring Question

[Turbo50stang]

I’m about ready to install a 2003 MM engine in a 99 Crown Vic P71 and have a few questions on rewiring the ECM. I’ve closely reviewed both vehicles PCM wiring schematics and noted there a few wires that must be relocated in the CVPI PCM wiring harness. Also there are a few wires that must be installed to allow for the addition of the MM injector pressure sensor, DPFE, knock sensor, etc.

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The questions I’m inquiring about are:

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1. Is there a signal I can provide to pins 17 and 18 to bypass the PATS since the CVPI does not have a theft system or is the only way to bypass the PATS is with a custom chip?

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2. Which pin goes to the alternator to control the WOT Alternator cutoff? Pins 7 and 70 indicate they go to the charge/start system and I’m not sure which one actually goes to the alternator.

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2003 MM PCM Catch Code is FDH2.

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Any help or recommendations will be greatly appreciated.

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Thanks

[KilledKenny]

1. Is there a signal I can provide to pins 17 and 18 to bypass the PATS since the CVPI does not have a theft system or is the only way to bypass the PATS is with a custom chip?

1. No. you will need the PATS transceiver antenna assembly wiring connector and 2 keys. The Transceiver is around the ignition lock cylinder. Best way to do this would probably find a junk 2003 or 2004 GM, MM or CV with pats. 2002 and older had a separate module for PATS so they would not work.


2. Which pin goes to the alternator to control the WOT Alternator cutoff? Pins 7 and 70 indicate they go to the charge/start system and I’m not sure which one actually goes to the alternator.

2. There are 3 pins used by the PCM for charging system. PIN 7 YE/LG is used for the stator terminal (S terminal) on the alternator voltage regulator. PIN 45 LG/RD is used for the indicator input to PCM ( I Terminal) PIN 70 YE is the output to the Charging system indicator warning lamp.

[RF Overlord]

2. Which pin goes to the alternator to control the WOT Alternator cutoff? Pins 7 and 70 indicate they go to the charge/start system and I’m not sure which one actually goes to the alternator.
I don't know if this will help, but the service manual reads as follows:

This system is unique in that it has two unidirectional communication lines between the PCM and the generator/regulator. Both of these communication lines are pulse-width modulated. The GENCOM line communicates the desired setpoint from the PCM to the voltage regulator and the GENMON line communicates the generator load and error conditions to the PCM.

So it sounds as though it's not as simple as "which pin" does the talking...you need both lines to make it work...

GENCOM is circuit 904 and GENMON is circuit 654...Circuit 904 is pin 45 (LG/RD) on the PCM...the service manual doesn't specify which PCM pin is circuit 654...

[KilledKenny]

GENCOM is circuit 904 and GENMON is circuit 654...Circuit 904 is pin 45 (LG/RD) on the PCM...the service manual doesn't specify which PCM pin is circuit 654...

circuit 654 YE/LG is the indicator circuit from the voltage regulator. It basically tells that there is a problem with the alternator and to switch on the charging system warning indicator.

[Turbo50stang]

Thanks for the information. I must have overlooked pin #45 since this was the old cylinder temp indicator position on the CV PCM. I'm assuming this wire is also coming from the alternator?

I've noticed on other forums that a custom chip could be burned to by-pass the PATS system. Can this be done with the MM PCM or am I required to use the transceiver antenna assembly?

[KilledKenny]

Thanks for the information. I must have overlooked pin #45 since this was the old cylinder temp indicator position on the CV PCM. I'm assuming this wire is also coming from the alternator?
Yes, it comes from the alternator to PIN 45 on the PCM.


I've noticed on other forums that a custom chip could be burned to by-pass the PATS system. Can this be done with the MM PCM or am I required to use the transceiver antenna assembly?

As far as I know you still need the transceiver antenna, The only chip I know of is for autostart systems. What they do is repostion the transceiver antenna under the dash and mount there own key chip on the antenna and program it to the vehicle. That is the only chip that the vehicle will use to start the vehicle so you can use regular keys You will need a min of 2 keys or chips in order to program the PATS system to operate correctly.