2000 DISCO II , OBD Code P0447

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bgbrown125

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The OBDII code P0447 states: EVAP Emission Control System Vent Open Circuit

What the heck is that, please????

Any help is appreciated.
 

Chongo

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CVS unit

2000 DISCO II , OBD Code P0447

The OBDII code P0447 states: EVAP Emission Control System Vent Open Circuit

What the heck is that, please????

Any help is appreciated.

PO447 = CVS valve, open circuit.

Resource: Discovery series 2 1999 / 2002 MY workshop manual
Page # 17-2-27

Following failures are possible:

connector or wiring fault / fuse / internal processor circuitry / external processor connections and related circuitry. PO447 through PO449

Valve stuck open or shut. PO446 through PO449

Valve blocked PO446

The valve is normally open in design, spring loaded open. The ECM closes this valve and shuts off the e-vap system to the fuel tank. Sensor in tank regulates the tank pressure differentials, i.e. vacuum.


Although this doesn’t pertain to your situation, others working on a similar issue to this may need this. The PO codes for tank pressure differentials are PO451- signal stuck high within range, PO452, pressure signal short circuit to battery, out of range “High”, PO453, pressure signal short circuit to ground or open circuit, out of range “low”.

The CVS solenoid, or “Canister Vent Solenoid” is mounted on a slide-on bracket which is riveted to the cruise control bracket at the right hand side of the engine compartment.
The fuse that powers this unit is in the engine compartment fuse panel and is the # 2 fuse.

I would strongly recommend cleaning the blades on the fuse and making sure there is continuity through the fuse, Check your power supply just before the fuse and after the fuse a good 12.2 – 12.6 volts eng. not running. and also check the fuse itself.

Second check is @ the connector which plugs into the CVS solenoid. One of the two wires is the ground wire, and check this with an ohm meter to ground, there should be “0.0000” ohms resistance between this connector and ground, if there is, you have a ground integrity issue.

Third check is with the engine running, back probe the power wire to see if the processor is sending current to the CVS solenoid. Snapping the throttle to W.O.T… condition not allowing it to rev very high should activate the CVS circuitry to close long enough to get a test light to illuminate or a value on an ohm meter. If the value is 0.000 v. then there is an issue with power supply either to or from the processor, and the issue can be the processor but most likely a connector or wiring.

Check the CVS unit for continuity: unplug the connector to the CVS unit connect the ohm meter to each terminal of the CVS unit, pos. to one end, neg. to the other. And you should get an ohm reading around .023 k ohms.
A lot lower or higher ohm reading means this CVS solenoid needs replacing. 0.0000 ohms means shorted internally, and infinity means open circuit. You can also wire up a 9 volt battery or the vehicle’s 12 volt battery and you can physically check its function, to see the CVS work.

Feel free to ask any questions…………

Best of luck to you……………..Chongo
:bandit:
 
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