My 1998 Maxima SE has a persistent CEL :
P1493 EVAP Canister Purge Control Valve/Solenoid Valve Stuck Open

I tested the Solenoid and it clicks when power is supplied, and the wiring into the solenoid tests OK

Using a new Vacuum gauge (that holds vacuum perfectly when I test it), I find that two ports on my Canister Purge Control Valve work as they should and one port closes when it should but has a slow leak. It's the port to the right side in the image I posted.

I test using a short piece of new tubing attached to the port. The new tubing is tested and has no leaks

I dosed the valve with PB Blaster and blew some air from a compressed air can through the ports. I tried the valve on the car again with same P1493 code triggering after less than ten miles. I cleared and tried again and the same code triggered again.

I took the valve off again and the same port had a slow leak.

So I got a used valve from the local boneyard, but that also showed a leak -- through the same port only. Others were OK.

I returned that valve, got another, and the same result: leak though the same port.

The odds of that happening three times seem pretty slim to me.

I'm wondering if a slow vacuum leak through that port is standard and I should be looking for a fix at something other than the EVAP Canister Purge Control Valve.

I hope someone can check his or her own EVAP Canister Purge Control Valve.on a car that does NOT throw a P1493 code -- and tell me if the same port leaks or holds vacuum.

 

Its the valve on the canister and no it should not leak

 

just to clear things up: The valve in question -- I included an image -- sits on top of the engine. It is part of the canister circuit, but it is nowhere near the canister.

I just thought it was strange that my valve and the two I obtained to replace it all had leaks when the nipple on the right side was tested. I have not seen many referenced to p1493 trouble codes, and yet the three 1493 valves all had the same leaky port.

Guess I'll have to order a new valve and hope that one doesn't leak AND fixes the code.

 

Have you noticed any small black particles coming out of the valves as you tested them? If the EVAP canister starts leaking the charcoal bits, they interfere with the valve operation, even though the valve is good. Another possibility is that the EVAP canister has water in it.

How to check - see page 23 (bottom) and page 419

http://boredmder.com/FSMs/Nissan/Maxima/1998/EC.pdf