I have a 1997 Neon and have a check engine light with the extracted code being 31 (a fault in the evap purge solenoid circuit). I pulled out the solenoid and checked it with a 12v source and it is fine. When 12v is applied it clicks and I can blow through it, when I remove the 12v I cannot blow through it. I checked the resistance and it is approx. 30 Ohm.
After reinstalling the solenoid:
When I turn the key to the start position (or turn engine on) I read 12v (or higher) on the wires going into the solenoid when disconnected from the solenoid. However, the moment I connect it to the solenoid, the voltage drops to zero right away (no clicking or anything). It is as if the PCM is supplying voltage, but is unable to supply the current needed to activate the solenoid. Is something wrong with the PCM / is there anything I can do to fix it ?
Also, with the engine running I checked the hoses going into the solenoid and one is definitely pulling a vaccuum, so I think that is fine. Also, on the wires going into the solenoid, one wire is definitely to chasis ground and the other is not (as I would expect). I also looked for an worn away / shorted wires, but could not find any.