Q: What will happen when a Ford ecm diode goes bad?

asked by on June 25, 2017

What would cause an ecm diode on 2011 Ford mustang 5.0 to go bad and what are the symptoms?

My car has 120000 miles.
My car has a manual transmission.

The PCM power diode is put into the fuel pump and PCM relay power circuit to prevent power surge feedback into the circuit called flyback voltage then can be higher than normal operating voltage. The computer may get flyback voltage surge and may damage power circuits inside the PCM is the diode was not used or is shorted across letting voltage to flow both ways.

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