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engine malfunction warning low voltage to circuit A

Axel Kaber
Axel Kaber
in Ford Focus Club

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Hi All,

I hope somebody can help me out here. My car wont start with engine malfunction warning. Garages were a total waste of time, eventually telling me to go through Ford dealerships because there was a software block on the ECU. But me and my mate managed to run an interface to Forscan and got error codes (attached) including a low voltage to circuit A. I noticed the position of the PCM on the ford (right in front of the passenger wheel arch) and wondered if it may be the reason for this fault, easily exposed to weather etc?

HAS ANYONE GOT EXPERIENCE OR ANY IDEAS FOR THIS? IS IT FIXABLE WITH DIY, AN AUTO ELECTRICIAN, OR NOT AT ALL!?

Google AI says: P0642, "Sensor Reference Voltage A Circuit Low," indicates a problem with the 5-volt reference voltage circuit for the engine sensors. This usually means the voltage being supplied to the sensors is below the expected level, potentially causing various driveability issues. 

Many thanks in advance for you time.

Alex

 

FordFocus Log r1.txt

  • Quote


    Damaged or corroded wiring harness to the PCM.

    P0642 is a code that has come up a few times on the forum.

    Take a read of this thread  (fast forward to 16th July to see the answer)

     

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