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JYL007 11-13-2012 02:33 PM

2001 ZX3 wiring diagram
I was looking for the wiring diagram of a 2001 Ford Focus ZX3. I am having trouble diagnosing a problem with my vehicle and would like to find the wiring diagram for it.

Readiness codes reset every time the vehicle is turned off. I need to know what wire is giving power to the PCM memory while the vehicle is turned off. Since right now it is losing its memory when the key is off.

B+ that is NOT controlled by the ignition or relay is what I believe is the failure. I do not want to replace the PCM without confirming this wiring to be good. Any help with finding PCM wiring diagrams would be great!!! I have tried Alldata and other online resources, they are all weak and incomplete. I believe Ford's schematics is the only way.


zetecDon 11-13-2012 04:18 PM

1 Attachment(s)
Moved to "General Technical Chat". I don't have the diagram myself but you can easily find one in a manual that you buy at an auto parts store. I have checked online but you have to be specific as to which wiring diagram that you need. If you are looking for a wiring harness that goes to the fuel injectors and other underhood electronics I have one that I some how received and haven't been able to get rid of it lol. It is for a 2000-2001 Zetec Focus. If that's what you need I can give it to you, all you would have to do is pay for shipping.

drewts86 11-13-2012 06:37 PM

Let me know which diagram you are looking for. I can scan it and e-mail it to you.

JYL007 11-14-2012 07:55 AM

The ECM wiring diagram is what I seek.

BC_ZX3 11-14-2012 09:58 PM

The battery is the only source of 12V power to the PCM with the ignition off - fuse 20 (10A).
Red wire from battery (always hot) to Battery Junction Box (BJB) and fuse 20 to PCM pin 55.
IMO, you should start by checking the battery connections for tightness and cleanliness and reseat the fuse. There is unlikely to be anything wrong with the wiring harness or PCM.

drewts86 11-19-2012 01:37 PM

Sorry I've been super busy at work with Thanksgiving holiday coming up. I'll try tomorrow evening to get the wiring diagram scanned and sent to you.

chuckdw 08-26-2014 08:56 PM


Originally Posted by drewts86 (Post 4454296)
Let me know which diagram you are looking for. I can scan it and e-mail it to you.

Would you please email me a wiring diagram of the cooling system? My resistor is good. Seems to be a temp sensor that provides ground for the engine fan for high speed only. Thank you. ps , I've spent hours checking . A diagram probly help a lot!

sailor 08-26-2014 09:14 PM


First post, eh? Asking in a thread 2 yrs old is a cross fingers, that person hasn't posted since May, yet might be on anytime.

Fan system doesn't work through a temp sensor grounding the fan.

Cyl. head temp sensor tells PCM the temp, PCM to low or high fan relay as needed.

Fan relay to fans for high, or fan relay to fan resistor to fans for low. (skipped fuse there, fan power to relay has to come from somewhere (grin))

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