1999 Mercury Villager - P0325 and P0135

Had both P0325 and P0135 appear at the same time. After replacing the O2 sensor, found out that I had short near the PCM. Corrected that and the P0135 code was corrected. Before I replace a good knock sensor, ($350 for the part and $500 labor), what do you recommend me trying to see if the is another short for the knock sensor?

It's always a good idea to test the circuit before jumping into a repair like that.

With that said, the knock sensor is a part that is known to fail on that engine. It should only store a code, but not turn on the check engine light. Normally there is no adverse affect on the engine. The sensor detects when an engine is pinging/knocking ans sends a signal to the computer at which time the computer retards the timing in order to control the pinging.

I've seen many cars with a stored knock sensor code and the customer just lets it go due to the repair cost. Right or wrong, that's what they choose to do. Just wanted to give you my input.

Good Luck