Evap can solenoid circuit trouble...

I am trying to troubleshoot this cel, for my 04 saturn ion. It is beyond my experience level as I am stumped.

The torque app and elm clone obdii scanner is telling me this.

P0449 Powertrain - Auxiliary Emission Controls - ISO/SAE Controlled Description EVAP Vent Solenoid Control Circuit Conditions Cause
Engine speed over 600 rpm, system voltage from 6-18v, then the PCM detected that the Actual and Commanded state of the Vent Control solenoid control circuit did not match for over 5 seconds.

I tried swapping the solenoid to no avail. There seems to be no shorting of the two wires that power the solenoid with the cars power off. One wire seems to have continuity with the chassis ground.

The solenoid clicks when voltage is applied out of the car. Is the problem between the wiring and the cars computer? Or should I be looking at the charcoal can and its wiring and function and the hose inbetween?

Last is there a certain point at which the computer opens or closes the valve, like turning the key to the on position?

In order for the PCM to know the solenoid was activated after power was applied to it, there has to be a sensor of some type. Either a switch that sees the solenoid activate or a pressure sensor seeing the EVAP vent in action.

So basically you are looking for what sees the solenoid working.

In reply to pjbgravely:

Thanks, I will start digging into the harness and see what the circuit runs into and go from there.

http://www.bbbind.com/free_tsb.html

Here is a website that will give you the TSB's and wiring diagrams for it (or any car). Should be helpful. I didn't see any tsb's for your code though.

In reply to gearheadmb:

Great site thanks, that should come in handy for this and some other problems alike.

Ok so new question, should solenoids have continuity when open and/or closed?

I was am thinking they should ( how else would the magnetic field be created) but the great world wild web has conflicting ideas about this.

The windings of a solenoid must have continuity at all times, or they are not a solenoid, they are scrap.

Streetwiseguy wrote: The windings of a solenoid must have continuity at all times, or they are not a solenoid, they are scrap.

Plus the switched terminals should have continuity as follows;

Normally Open (NO) relay, switched terminals have continuity when power is applied to the windings.

Normally Closed (NC), relay switched terminals have continuity when NO power is applied to the windings.

Thanks for confirming that guys.