Focus Fanatics Forum banner

41 - 43 of 43 Posts

·
Registered
Joined
·
4,397 Posts
Marde,
On my 2005 diagram (crappy scan attached) SIGRTN for TPS - and many other things - is definitely C175b-41 (near bottom of diagram). Interestingly C175t-41 is also SIGRTN but exclusively for the TSS in the AT....
Thanks for the reply and other info.

Pls allow me to re-address the OP issue -and- our comments in separate containers.

#1 - The PCM should be compatible and pin-out the same in 2004-2007 (and only if the 2004 is Duratec engine). The part numbers of these PCM's during these years should be the same or might be different, but compatible with one another. Right? TBD.

#2 - The schematic typo(?) use, or re-use of C175T verses C175B (pin-41) might be nothing to be concerned about IF the PCM is able to receive this RTN signal on either connector (B or T) on pin number 41. I believe & guess the PCM is able to operate all these 5V VREF senors & operate the engine normal if the RTN signal arrives at pin-41 at the T or B connector. This would allow a 2004 PCM to be interchanged with a 2005 PCM. This, despite our wiring schematic differences of B verses T connectors... the PCM should have this design flexibility in the hardware, the external senors used, and firmware used within PCM.

... Interestingly C175t-41 is also SIGRTN but exclusively for the TSS in the AT.
Yes, I see that also. And not. In my book, it is not exclusive.

The TSS with an auto-transmission ties into (wire spliced in at S201) into the RTN signal. But, again, the same end point is at C175T pin-41 ((in my book)).


...However Im not convinced the high RPM is caused by the low VREF voltage or is causing it...
And here we do not agree. If the 5V VREF is low (at 1.5V???) this will effect many other sensors AND therefore many inputs to the PCM. So the PCM is drunk or stoned based on bad info from these sensors because of bad (too low) VREF.

The PCM could respond with running the engine at high RPM because of this low voltage VREF situation.

Yes I have the 2005 book. I can see that the 2004 Duratec PZEV 2.3 is different as I have access to those schematics online. You know Ford loved to change things year-to-year.

Paul
Yes. I do. I have heard many-many stories about slight and big differences between the car years. But I only have one wiring diagram book. 2004.

Thank you Paul for your time and effort here for me and the OP.

Cheers!
 

·
Registered
Joined
·
16,046 Posts
Post #36 has a possible conclusion to this.

I for one do not allow for TPS error alone to make the rpm go up that much but if anything else (sensor) is tied into the same Vref input then no telling what can happen then, all bets would be off.
 

·
Registered
Joined
·
36 Posts
Vacuum test, try smoking the intake, if you only smoke the crank case you won't get any smoke in the intake unless the pcv is connected.
 
41 - 43 of 43 Posts
Top