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lamontgomery, Ford Mechanic
Category: Ford
Satisfied Customers: 467
Experience:  14 years experience, 2000-2006 Senior Master, ASE master in Truck and Auto, Level 1 Fire mechanic
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what dose code PO355 mean

Customer Question

the truck runs rough, very bad gas milage, when traviling 40mph or so then it really jerks. I ve changed the plugs,fuel filter and coil. should i try the injector next.
Submitted: 9 years ago.
Category: Ford
Expert:  lamontgomery replied 9 years ago.

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.

lamontgomery and 4 other Ford Specialists are ready to help you
Customer: replied 9 years ago.
Reply to lamontgomery's Post: so whats a pcm and how do i check the ground?
Expert:  lamontgomery replied 9 years ago.

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.

Please accept my answer if you are satisfied.

Thank you,


Customer: replied 9 years ago.
Thats what iam talking about Gomery. Thank you for your time and expertise. Have a good day.
Expert:  lamontgomery replied 9 years ago.
Thank you for the accept!