Ford Repair Questions? Ask a Mechanic for Answers ASAP
P0355 is an electrical fault with the #5 ignition coil, make sure it's plugged in and that you are receiving B+ and a ground from the PCM when the engine is running.
The powertrain control module (PCM) is the computer the monitors and controls all engine and transmission computer inputs and outputs. If it finds a problem on any of these circuits, it lets the driver know by turning on the light. The code you pulled is an electrical fault for the #5 ignition coil. This would be the 1st cylinder on the LH side of the motor. This fault can be as simple as a the coil not being plugged in. Try clearing the codes, swap the #5 coil with the #6 coil. Run the engine, and if P0356 sets, you have a bad coil. If it stays the same you will need to test the wiring to the #5 coil, plug in the coil and back probe the connector with a needle or paper clip (one at a time) Using a test light, you should have B+ (solid light) on one wire, and a flashing light on the other. If you do not get these results, you will be looking for a wiring problem from the PCM to the #5 coil.
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