Hi Jim,
I have the Check Engine Light with error code P1457 on my 02 Accord 4 cyl. Vtec engine. I looked at the EVAP Shut off valve, the two screws that hold this valve are corroded badly. I unplugged the connector and measured the voltage and the voltage reading was 0V. I got the same reading with key in II and with engine running. Do you have a wiring diagram of this connector? One of the wire must be broken somewhere up stream.

Thanks,

Will

 

Key on, one wire should have battery voltage. Probably through the main relay.

The other wire goes to the ECU, which connects it to ground when it wants to open the valve.

That valve doesn't operate all the time. Only occasionally, when the ECU decides to test the system.

 

Thanks Jim. I just realized that I made a mistake by measuring the voltage across the two pins on the connector. I will do the measurement again tomorrow.

 

Yeah, when the ECU is NOT energizing that solenoid, you would have measured about zero volts. You want to measure to ground. Once you see which wire is "HOT", you can ground the OTHER wire to energize the valve & verify that it clicks open.

 

Another method of testing the EVAP shut valve manually is to use the power from the disconnected connector and ground the appropriate pin on the EVAP Shut valve. The EVAP shut valve on my Accord is operating normally. There must be a leak somewhere in this EVAP system. I will troubleshoot this issue later. Thanks.

 

Jim -

Sorry that it's been so long since I last checked in - about the last time I talked to you I was coming off of spring break, so I had to set the troubleshooting aside while I finished the semester. In addition, I have only recently (last Sunday) actually found and fixed the problem with the EVAP system. The problem was actually a lot more simple than I had thought it would be - a broken wire. Actually, it was two broken wires and one that was partially broken.

It appears that something damaged part of the wiring harness for the two valves and FTP sensor for the system near where the lower control link for the rear suspension meets the chassis (on the driver's side). What it could have been is beyond me. It had to be a fairly sharp object, because it cut through the plastic corrugated duct holding the wires also, and it looked to be a fairly clean cut. The result was that the 12V for the Vent Shut Valve and the Bypass Valve were taken out. I should mention, however, that the wire for the Bypass Valve must have been making contact intermittently, in that the first time I tested that circuit everything checked out, yet when I installed a new valve (anyway) it only appeared that the new valve didn't work because the wire wasn't conducting at that point. I spliced the wires back together, and dressed the harness so that now it actually is tucked up behind the EVAP cannister - hopefully this won't happen again. The check engine light went out in about two days, and the vehicle passed emissions.

A couple of things I wanted to mention regarding the troubleshooting, that may help others with this problem:

You will see the ECM output stages (approx. 700 ohms) when the ignition is on while testing the return for the valve circuits. This reading will go wide open when the ignition is turned off. I was initally confused about this, and as we discussed thought there might be an issue with the ECM.

All of the 12V for the valves are on the same circuit, so if you see power on one or two of the valve circuits, and not on the others, you're looking for a broken wire(s), not a fuse or bad component necessarily.

I found that the best way to address the canister troubleshooting or Vent Shut valve replacement is to simply remove the canister alltogether (I read a lot about broken screw heads). The canister is fairly easy to remove - remove the hoses, one bolt, and the quick disconnect for the fuel tank vent hose and it's out. Then you can saturate the screws with penetrant, and while standing the cannister on its flat end, put enough downward pressure on the screws to break them loose without stripping the heads. Also, it's easier to block all of the ports to test the cannister for vacuum as well.

Finally, don't take any shortcuts. The troubleshooting procedures in the factory service manual are straightforward, and if they are followed will indeed lead you to the problem (I recommend the factory service manual - it's also available on CD-ROM). While I think I came out ahead overall (when compared to the cost of the dealership to fix), I did purchase two valves that I didn't need. I was under the pressure of an emmissions test deadline (or so I thought - they will give you an extention if you show you're working on the problem), so I can't beat myself up too much. But I sure could find better ways to spend $100.

Jim, again thanks for your help!

R,

Rob

 

I had the 1457 code on my 99 Accord and decided to buy a new vent shut valve from a Ohio dealer off of Ebay. ($45) I took the advice of several on this board and removed the entire canister with the valve on it. That was the smart move. It only took about 15 minutes to remove all of the hoses and 3 bolts and drop the canister. I then took it over to my workbench. The screws holding the valve were totally rusted thru and locked down tight. It took some vise grips to loosen them up working on my bench. After working it loose, it was clear there was NO way I was going to remove those screws with the canister on the car. No room and no leverage. Once I broke the rust seal, it took a few seconds to remove the old valve and install the new one. Another 10 min to get the canister back on, and that was that.

So far (3 days) the MIL light has stayed off! Again....don't try to remove the valve while on the car!! Remove the canister and work it on your bench.

--Jeff

 

Thanks to both you guys. It's always nice to hear when something works. Too often we try to help someone & then they dissappear so we never know if they fixed it.