Ford Expedition The Expedition provides the feel of a full size truck with the seating of a large SUV.

PCM relay issue

Old 05-02-2019, 02:22 PM
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Join Date: Jan 2009
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Default PCM relay issue

I have a 2003 Expedition with the 4.6. I was having misfire codes and so I changed the plugs and coils. When I went to start it, I turned the key and got nothing. No cranking even. I discovered that fuse 34 had been blown. That fuse was for Mass Air Flow (MAF) sensor (12B579), Powertrain Control Module (PCM) (12A650), Fuel injectors, Idle Air Control (IAC) valve (9F715), Fuel pump relay. I disconnected the MAF, The PCM relay, and all coils and injectors. By process of elimination I was able to connect everything except the PCM power relay without blowing the fuse. I went out and bought a new PCM relay and the same thing happens. I cleaned battery terminals and any other corrosion that I could find. Still having the same issue. Not sure where to start to look next. Any input would be great.
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