Questions and Answers

Plymouth Neon DTC P0445 Q. Hey Vincent, I have a 1998 Plymouth Neon, 146,000 miles, 2.0 liter SOHC engine, however the Check Engine Light is on. I took it to AAMCO and the code P0455 - Evaporative Emission System Leak came up. What could cause this and how much will it cost to fix? Thanks a lot, Lorry

A. DTC P0445 "Evaporative Emission Control (EVAP) System Leak Detected (gross leak)" This is a very common code to pop up. 99 times out of 100 it is caused by a loose or bad gas cap. In fact some late model cars have a "Gas Cap Loose" light that comes on when this code is thrown.

If the gas cap is good and correctly sealed, then an EVAP pressure tester needs to be attached to the EVAP system and the leak found. It could be anywhere in the system so it is difficult for me to estimate where it is and how much it will cost to repair.

If the gas cap is loose, and you tighten it, the Check Engine Light (CEL) will not go out immediately, but will take some time to go out after the PCM tests the system three times.