smee123

Some quick consideration for you guys. Background on my car : purchased from someone on the site that replaced the solenoids as well as the canister. Purchased knowing it throws this code. Did a quick test to get it to throw it. Filled it up and put it in the garage hot. Next day took it out. Warmed it up and then gave it a good Italian tune up. Code came on right away after the fourth time into vtec. Reset the code and drove 110 miles to expel a half of tank of gas. Let the car outside overnight. Opened the fuel filler cap and got rid of whatever pressure there was built up. Drove the car for 15 mins. All readiness set. Drove it hard for a bit and no check engine light.
The conclusion I have come to is that over time, and many heating and cooling cycles, the pressure sensor's performance degenerated to the point where high tank pressure/vacuum throw it out of wack. With a full tank of gas the gasses produced are under significantly higher pressure versus a tank that is half way or three quarters full. I don't care enough to actually put a new one on there , so just throwing it out there for anyone that is still chasing this down. For the record, this car has north of 200k miles and no mention of sensor replacement.

Haywardmagana97

@Billman250 Hi I’m a new member to the forum, although I’ve been using s2ki for the last 3 years of ownership of my ap1. Ive never had a reason to make an account but it seems it is the only way to purchase your TCT. What would be the most efficient way of getting in touch with you for purchase of this part?

Billman250

Available through S2ki PM only. It will be approximately two weeks before you can PM members if you are a new Acct user.

Haywardmagana97

Appreciate the response. Ill be getting in touch with you once the pm access is available.

Clicker10

Mr. Billman,

I'm getting the cursed P1457. I replaced the evap two way valve and the evap bypass valve to no success. I can't pass emissions. Any suggestions?

Billman250

The moaning is likely pressure against the evaporative diaphragm, signaling one of the 3 evap valves is inoperative. Rarely, if not ever, will an all oem S2000 have a leak (the ECU sees the evap pressure change and interprets as P1457)

Test all 3 valves. The right scan tool can access and operate, or make the homemade test harness.
-EvB (Bypass)
-EvV (Vent)
-EvP (Purge)

Billman250

Car here this week, P1457, bypass valve salted/shorted, also shorted Bypass Valve Control Signal from ECU, needed ECU as well.

Car Analogy

The photos from when the thread was started are no longer there. Maybe someone still has them and can repost them?

S2KHANG

If anyone wants new EVAP stuff to clear their P1457 code, DM me. I have a complete set brand new, never installed.

I once got the P1457 years ago and bought the EVAP stuff new from majestic. Since it wasn’t my daily at the time, I never got around to installing it. Randomly one day, the code went away and hasn’t come back on for well over 20K+ miles.

EDIT: I recently sold my EVAP stuff. Cleared the buyer’s P1457 CEL!

Live Fast

I bought a low mile AP1 from it's original owner in Florida and drove it 800 miles back home. I did remove and clean the air-box but forgot about the vacuum linee on the back and tugged a few times before checking.

Pretty sure that caused a tear. I also cleaned the engine bay with a hose and a lug nut brush. I also touched on the grounds next to the passenger side horn and driver side near the coolant overflow.

I let it sit overnight before starting and after a bit of driving I'm getting P1457, Emissions control Leak B, and 61-1-Battery Voltage Malfunction.

Edit 1: It turned out to just be the P1457 after some driving. I ended up putting some dielectric grease on the grounds to help keep them in good shape.

I did use some gator clamps and a 9V to test what I thought was the EVAP Bypass but in this diagram below it's the ACVVC Solenoid Valve. It did click and I could suck/blow through it.
The check valve near it however I could not suck/blow through it. I did replace the vacuum lines going up from the Vacuum Tank below them and to the hard metal tubes using silicon tubing.
2 tanks of fuel (1/4 to 3/4) and 2 readiness tests and it seems like no CEL with no pending code.

Here's a picture of the vacuum line routing
​​​​​​​Edit 2:
CEL did come back on my third tank (1/4 to 3/4) and I believe I will test the actual EVAP Purge valve from this diagram above. Using Honda's Parts Diagram it looks like the Purge Joint has 3 ports vs the Check Valve that only has the 2.

​​​​​​Edit 3: Using a 9V battery and some alligator clamps I did test the connections. Directly down from the IACV it does click. The one on the air box also clicks.

Underneath the car behind the EVAP shield the orange connector didn't click nearly as loud.
I also felt it would be nice to add some pictures to show that area since the other have been removed.