I have a 2000 Civic with CEL on. code is P 1457. Valves, gascap replaced. Please help my Honda!!?

Question

The CEL light keeps coming back on, so I always have to reset the computer.. Noone can figure out what the problem is.. The gas-cap is brand new, the purge valve is replaced.. And I keep getting the same code. Plese give me an answer 'cuz I'm going nuts..

Answer 1

This code is generated during the EVAP and purge sequence of computer testing. It will only turn on the light after two consecutive failed trip drive cycles.
This code is set for a failure of loss of vacuum through a leak less than 0.040".
This is a very small leak, but large by CARB and EPA standards. It doesn't NECESSARILY mean that there is a component failure. There could be (and most likely is) a plumbing leak, either at the tank, or the EVAP canister or ANY of the connections associated with the EVAP atmosphere.
You can go along and throw parts (pronounced MONEY) at the problem,and never actually repair the failure.
This diagnosis really does require a specialized piece of equipment and a bit of savy about how HONDA has assembled their car, and how its computer runs its tests.
A good emissions tech or HONDA tech will use a "Smoke Machine" to focus on the whole system, along with the scanner to watch the progress during the test, observing the vacuum decay during the test.
There are several factors required for the car to run the test:
1) Fuel between 15% and 85% full. If the contents are outside this range, the car will not run the test.
2) The car must be started with the temperature of the coolant and the air intake temperature must be within 10° F, and must be a COLD start.
3) the computer must be able to cause a vacuum in the fuel tank, and then watch the decay time.

This is a bit more complex than the average do it yourselfer has the time, equipment or knowledge to address.
Take it to an emissions or Honda tech.

Good Luck

Answer 2

Go to the dealership and get them to do a evap smoke test where they pump smoke into the evap system. Where the smoke exits the system is where your leak is.