Rebuilding 03 Town car P0355

Thread starter #1


Junior Member
Hey guys I'm rebuilding a 03 Town car When I come up on the rest of the money right now I'm driving it and it's throwing a P0355 code I tested the spark plugs and cylinder 5 is not sparking any ideas? Also if anyone whould like to help me my engine or exhaust is making a putting noise while it's at idle I appreciate it.
Last edited:


Senior Member
Ottawa Ontario Canada
The P0355 is a problem in the circuit from the PCM to the COP. Since you have eliminated the COP internal circuits, check the connector plug for corrosion or loose/pushed out connectors. If all looks good then check the wires for a grounding issue or broken wire.

Here is a video that will help you:

The putting noise is likely an exhaust leak. Sources would be the exhaust manifold or its gasket at the cylinder head or a cracked manifold or problem connection. Listening for the area of the noise would be the first step, then using your fingers to feel for the escaping gas. The procedure is best done with a cold engine since the leak will likely be worse, however, the exhaust heats up quickly.
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