2000 Cadillac deville 4.6 P0443.I have checked both the vent valve and the solenoid both work when batt volt applied out of circuit both connectors show batt voltage with key on . What am I missing?

P0443 Evaporative Emission Control System Purge Control Valve Circuit
P0443 - Evaporative Emission Control System Purge Control Valve Circuit

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The Evaporative Emissions System (EVAP) allows fumes from the gas tank to enter the engine to be burned, rather than vented into the atmosphere as an emission. The purge valve solenoid is supplied switched battery voltage. The ECM controls the valve by operating the ground circuit, opening the purge valve at specific times allowing these gasses to enter the engine. The ECM monitors the ground circuit as well, watching for faults. When the purge solenoid isn't activated, the ECM should see a high voltage on the ground circuit. When the solenoid is activated, the ECM should see the ground voltage pulled low, close to zero. If the ECM doesn't see these expected voltages, or senses an open in the circuit, this code is set. Note: This DTC is similar to P0444 and P0445. Potential Symptoms P0443 trouble code symptoms could be just an malfunction indicator lamp (MIL) illumination. There may be no drivability problems at all. But, it's also possible to have a lean condition or a rough running engine if the purge valve is stuck open. Usually though, these symptoms are accompanied by other EVAP codes. Another symptom may be excessive pressure in the gas tank in the form of a "whooshing" sound when the cap is removed, indicating a purge valve that isn't working at all or stuck closed. Causes To cause a P0443, there has to be a problem with the purge control CIRCUIT, not necessarily the valve. Usually they are a unit housing the valve and the solenoid as an assembly. Or it could be comprised of a separate solenoid with vacuum lines to a purge valve. That said, it could be any of the following: Bad purge solenoid (internal short or open) Wiring harness chafing or rubbing another component causing short or open on control circuit Connector worn, broken or shorted due to water intrusion Driver circuit inside powertrain control module (PCM) is bad Possible Solutions 1. Using a scan tool, command the purge solenoid to activate. Listen or feel for a clicking coming from the purge solenoid. It should click once, or on some models it may click repeatedly. 2. If it doesn't click with scan tool activation, unplug the connector and examing the solenoid and connector for damage, water, etc. Then check for battery voltage on the feed wire with the key on. If you have battery voltage, then ground the control side manually using a jumper wire and see if the valve clicks. If it does, then you know the solenoid is working properly but there is a problem with the control circuit. If it doesn't click when you manually ground it, replace the purge solenoid. 3. To check for a problem on the control circuit (if the solenoid tests okay and you have voltage to the solenoid) plug the solenoid back in and remove the control circuit (ground) wire from the ECM connector (If you're unsure how to do this, do not attempt). With the ground wire removed from the ECM, turn the key on and then manually ground the Purge valve control wire. The solenoid should click. If it does, then you know there is no problem with the control wire to the solenoid and there is a problem with the ECM purge solenoid driver circuit in the ECM. You'll need a new ECM. However if it doesn't click, then there must be an open in the wiring between the ECM and and the solenoid. You must find it and repair it.

Read more at: http://www.obd-codes.com/p0443
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the codes should be addressed in the order they show up, so starting with the P0443 (it's a zero not an o after the P, the P refers to a powertrain code).
Have you replaced the purge valve itself, often times this will rectify the trouble.Open the gas cap after driving a while , do you hear a "whoosh" of pressure release? If so likely the valve itself is defective.Replace it reset the MIL and drive to see if light comes back on, if it does ,rescan to see if 443 is still present, if not then move on to new first trouble code.
(fyi)
To cause a P0443, there has to be a problem with the purge control CIRCUIT, not necessarily the valve. Usually they are a unit housing the valve and the solenoid as an assembly. Or it could be comprised of a separate solenoid with vacuum lines to a purge valve. That said, it could be any of the following: Bad purge solenoid (internal short or open) Wiring harness chafing or rubbing another component causing short or open on control circuit Connector worn, broken or shorted due to water intrusion

check for blown fuses

when the car is off it has to vent so you can you can fill the tank a scanner can be used to close the vent valve but for a po443 i would say it is the
purge valve or wireing
with the key on 12 volts must come to the pink wire the solinoid should be about 20 ohms andcheck the comtinuity of green/white wire pin 42 on the ecm

DTC P0443 - Evaporative emission control system Canister Purge control valve (CANP) or vapor management valve (VMV) circuit malfunction.
Your cars computer is telling you there is a leak. But most of the time when the system is smoke tested, the tech comes up empty handed. This is because the leak is intermittent. There are several solenoids that can do this on your evap system. The purge valve and the vent valve are the most common. Looks like it is going to be your purge valve.

That said, it could be any of the following:

Bad purge solenoid (internal short or open)
Wiring harness chafing or rubbing another component causing short or open on control circuit
Connector worn, broken or shorted due to water intrusion
Driver circuit inside powertrain control module (PCM) is bad


Code P0443 - Evaporative emission control system Canister Purge control valve (CANP) or vapor management valve (VMV) circuit malfunction. The PCM expects to see battery voltage when the solenoid is commanded off and voltage under 1 volt when the solenoid is commanded on.

Enabling conditions: Run engine off and running self tests to check this code. Blocking Action: This code can block the following monitors: Fuel Control, O2 monitor, Catalyst Monitor, misfire monitor. Testing: Check to see if the purge solenoid will block vacuum when it's off and pass vacuum when it's turned on. Typical resistance is 50 to 100 ω.

Hope helps.

Hi, your vent valve has malfuntioned. The vent valve is near the tank, and has a hose to the tank and a solenoid to close it. Check the wiring/connector. If OK, try applying 12 volts directly to the solenoid. If it does not click when voltage is applied, replace the solenoid/valve.

P0446 Evaporative Emmission Control System Vent Control Circuit OBD-II Trouble Code Technical Description

Evaporative Emission Control System Vent Control Circuit Malfunction
What does that mean? Evap vent valve has only one purpose. It closes in order to seal the vent so the EVAP system can pressurize and ensure there are no leaks. Evap vent valve is usually supplied Batt. voltage with key on. The ECM's driver controls the ground, and when grounded, activates the valve (closing it). If the ECM detects a short to ground, and open,or a short to battery voltage on the control circuit, P0446 will set. Code also may refer to ECM detecting that EVAP system is unable to achieve or maintain vacuum during test.
Symptoms There will be no obvious symptoms to driver, other than MIL illumination.
Causes A code P0446 could mean one or more of the following has happened:

• Faulty vent valve
• Open, short or excessive resistance on Vent valve control circuit
• Blockage of vent valve
• Bad PCM

Possible Solutions With a P0446 OBD-II trouble code, here are some things to try:

• Replace Vent valve
• Repair open, short, or resistance problem in control circuit
• Repair open, or short, or resistance problem in power circuit
• Replace PCM

From: http://www.obd-codes.com/p0443 P0443 - Evaporative Emission Control System Purge Control Valve Circuit OBD-II Trouble Code Technical Description

Evaporative Emission Control System Purge Control Valve Circuit
What does that mean?

The Evaporative Emissions System (EVAP) allows fumes from the gas tank to enter the engine to be burned, rather than vented into the atmosphere as an emission. The purge valve solenoid is supplied switched battery voltage. The ECM controls the valve by operating the ground circuit, opening the purge valve at specific times allowing these gasses to enter the engine. The ECM monitors the ground circuit as well, watching for faults. When the purge solenoid isn't activated, the ECM should see a high voltage on the ground circuit. When the solenoid is activated, the ECM should see the ground voltage pulled low, close to zero. If the ECM doesn't see these expected voltages, or senses an open in the circuit, this code is set.
FB.init("dd7d9e9681341cde77587bc6a2029f6f"); OBD-Codes.com on Facebook Potential Symptoms

P0443 trouble code symptoms could be just an malfunction indicator lamp (MIL) illumination. There may be no drivability problems at all. But, it's also possible to have a lean condition or a rough running engine if the purge valve is stuck open. Usually though, these symptoms are accompanied by other EVAP codes. Another symptom may be excessive pressure in the gas tank in the form of a "whooshing" sound when the cap is removed, indicating a purge valve that isn't working at all or stuck closed.
Causes

To cause a P0443, there has to be a problem with the purge control CIRCUIT, not necessarily the valve. Usually they are a unit housing the valve and the solenoid as an assembly. Or it could be comprised of a separate solenoid with vacuum lines to a purge valve. That said, it could be any of the following:

• Bad purge solenoid (internal short or open)
• Wiring harness chafing or rubbing another component causing short or open on control circuit
• Connector worn, broken or shorted due to water intrusion
• Driver circuit inside powertrain control module (PCM) is bad

Possible Solutions

1. Using a scan tool, command the purge solenoid to activate. Listen or feel for a clicking coming from the purge solenoid. It should click once, or on some models it may click repeatedly.

2. If it doesn't click with scan tool activation, unplug the connector and examing the solenoid and connector for damage, water, etc. Then check for battery voltage on the feed wire with the key on. If you have battery voltage, then ground the control side manually using a jumper wire and see if the valve clicks. If it does, then you know the solenoid is working properly but there is a problem with the control circuit. If it doesn't click when you manually ground it, replace the purge solenoid.

3. To check for a problem on the control circuit (if the solenoid tests okay and you have voltage to the solenoid) plug the solenoid back in and remove the control circuit (ground) wire from the ECM connector (If you're unsure how to do this, do not attempt). With the ground wire removed from the ECM, turn the key on and then manually ground the Purge valve control wire. The solenoid should click. If it does, then you know there is no problem with the control wire to the solenoid and there is a problem with the ECM purge solenoid driver circuit in the ECM. You'll need a new ECM. However if it doesn't click, then there must be an open in the wiring between the ECM and and the solenoid. You must find it and repair it.

sad to say that you miss on what you did, dtc P0449 was related to vent solenoid contol circuit, purge problem indicates P0443,, check the vent valve connectors supply voltage from the power distribution box, (fuse # 14-tcm/batt) and the other wire(almost white) to ecm C1 #61.

maybe a fuse is blown? did you have the mechanic check the fuses? or even check all your relays and wiring?