Code P0355, no power to the number 5 coil?

STEVE2878

MEMBER
2001 FORD F-150
5.4L
V8
2WD
AUTOMATIC
135,000 MILES

I recently purchased the truck listed above Super Crew. It was idling and running very badly. I checked it with a scanner, and it said p0355 was the code which came up, bad coil pack. Replaced coil pack, check injectors all working fine. But come to find out check for fire at the connector and I am not getting no power to the number 5 coil. Some people have been telling me it may be the PCM might be bad and the circuit to the number five coil pack may be going out. If there's anyone out here that can help, I would really appreciate it.

Tuesday, December 6th, 2022 AT 7:10 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi,

If it is only one coil that doesn't get power, then the issue must be in the wiring harness at the coils.

If you look below, I attached the schematic of the coils. When you check for power, are you checking the red wire with the light green tracer? If so, and the other coils are getting power, remove the wire loom on the harness to that coil and follow it to where there is a splice and check if power is lost there. It is splice number S162. That is where the wires connect for coils 5, 6, 7, and 8 power supply.

If you do have power at coil 5, then we need to check for a ground path being provided by the PCM. To do that, simply disconnect the coil connector. Using a test light, attach the side with an alligator clip to the battery positive. With the light, probe the light green wire with a yellow tracer on the cylinder 5 coil connector which runs to the PCM. Have a helper crank the engine. If the PCM is providing a ground path, the light will flash on and off.

Let me know what you find.

Take care,

Joe

See pic below.

Image (Click to make bigger)