Code p0201, occasionally going into limp mode when driving, could it be the fuel injectors?

2009 FORD FIESTA
87,000 MILES • 1.4L • TURBO • 2WD • MANUAL
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JCMICHAEL
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Hi. My wife's vehicle occasionally goes into limp mode when driving long distances. I've since scanned the car and p0201 fault. Injector #1 circuit open/shorted. I've carried out numerous tests, and found a high voltage drop on injector feed wire. There is only 1. 2 volts on injector feed wire rising to 5v with engine running. I've stripped the wire harness down looking for a partial break or corrosion and found nothing. The only thing I did find was the wire braid on the starter motor was badly corroded and frade. I've since had that repaired and will connect it back up tomorrow. Not sure if that's going to solve the problem. If it doesn't, I'm at a dead end without a wiring diagram for the fuel injector circuit. I also carried out all testing with the injectors unplugged and tested the injectors as well. Injectors are with spec. I've got 1.2 v with injectors unplugged and I also unplugged the wire harness that supplies power to injectors and glow plugs. I'm also getting 1.2v at that multi plug as well so the problem is before that. Can anyone help?
Nov 26, 2022 at 1:10 PM
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JCMICHAEL
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I also carried out all testing with the injectors unplugged and tested the injectors as well. Injectors are with spec. I've got 1.2 v with injectors unplugged and I also unplugged the wire harness that supplies power to injectors and glow plugs. I'm also getting 1.2v at that multi plug as well so the problem is before that.
Nov 26, 2022 at 1:19 PM
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JACOBANDNICKOLAS
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Hi,

The Fiesta wasn't offered in the US in 2009. It was in 2011, but we have a gas engine 1.6L. I believe you have a diesel. Is that correct?

Let me know. I'll try to help in any way I can.

Take care,

Joe
Nov 28, 2022 at 8:55 PM
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BORIS K
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Hello,

I have looked at the wiring diagrams available. There is very little information on your type of engine.

I would suggest first checking the internal resistance of cylinder 1 injector. Using a multimeter/voltmeter measure pin to pin and compare with a good injector on cylinder 2.

A good video:
https://youtu.be/IFSu08og3TA

Hope this helps.
Cheers, Boris

Nov 29, 2022 at 9:40 AM
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JCMICHAEL
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Already did that mate. Everything tested fine.
Nov 29, 2022 at 11:30 AM
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JCMICHAEL
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Does anybody have a wiring diagram please?
Dec 1, 2022 at 2:14 PM
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JACOBANDNICKOLAS
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Hi,

I noticed Boris hasn't been back in touch with you for a couple of days. By chance, have you made any progress?

If I recall, you have low voltage to the injectors. Have you been able to find the cause?

Let me know.

Joe
Dec 1, 2022 at 2:17 PM
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JCMICHAEL
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Hi Joe. No one has been in touch. I still haven' found the problem. It's definitely not the injectors because I've tested them, and I also tested the wire harness separately. There's two wire harnesses. 1 is the main engine harness and the other is for the injectors and glow plugs. The main engine harness plugs into the second one so I disconnected the main harness and tested these. The 1.2v is in the main harness yet there is no partial break. Thanks for your reply.
Dec 1, 2022 at 2:46 PM
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JACOBANDNICKOLAS
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Hi,

If there are no breaks in the wiring, have you confirmed the connector pins are not corroded, loose, or damaged in any way? Also, if you go to the control module and check there, is the voltage different? I ask because if you are finding 1.2v at the module, my first guess is the module itself is faulty.

Let me know.

Joe
Dec 1, 2022 at 9:12 PM