Dtc P0443

kennystruck · October 24, 2008

I am getting the DTC P0443. Something about the purge valve solenoid circuit. I have my own code reader and basic hand tools but none of the specialty stuff. What would you suggest? Where is the purge valve solenoid located?

jackyshaikh · October 24, 2008

Your link is about canister vent valve,and this DTC is for purge valve solenoid.

Anyway the control module controls the EVAP canister purge valve ON time by grounding the control circuit via an internal switch called a driver. If the control module detects an incorrect voltage for the commanded state of the driver, DTC P0443 sets

If you have good electrical knowledge,check and test the circuit,if its ok change the purge solenoid

see the location

kennystruck · November 1, 2008

Well you did put on a used solenoid, could be that it is no good.

You have 11.8v on that wire, it should be battery voltage so check to see what that is.

I use a test lamp on these type of circuits because it is possible to have enough voltage but have a poor connection that sucks the necessary amperage to drive the circuit.

As I stated earlier if the positive circuit is ok and the valve is ok then you should probably take it to someone that has the proper equipment and know how.

Good luck.

Mike, First off let me say Thank You, I really appreciate your help.

I did check the battery voltage and it was higher, something like 12.4v or 12.6v.

The solenoid was a "take off" and was spotless, it even had a blue cap on the canister port...looked very factory. You are right though...it could be bad.

I'll rig up a test lamp and see if it flashes (or should it go on fully).

If the wires or connections are bad how do I check that. Continuity check between PCM end and valve end?

I have dealt with PWM solenoids before. I believe the "driver' is a bit of software, correct? If the wires and connections are good, the valve is good, would a replacement PCM solve this? Is it possible to "reset" or reprogram of the PCM?

I have located a company that will program the PCM to my vin number, they are about $100. Is PCM replacement something that the shadetree mechanic can undertake?

This is the claim about thier product

******GM installed this 12200411 ECM in all of the above applications. This was possible because each of these models received their specific programming from the factory. In other words, you can't simply swap a used ECM from one vehicle to the next. We are a licensed user of the same GM software that a GM garage would use to reprogram and update your computer. With your purchase we will reprogram the ECM, with the latest software updates available from GM, to your specific vehicle using your VIN (vehicle identification number)

Phillip · October 24, 2008

Your link is about canister vent valve,and this DTC is for purge valve solenoid.

Anyway the control module controls the EVAP canister purge valve ON time by grounding the control circuit via an internal switch called a driver. If the control module detects an incorrect voltage for the commanded state of the driver, DTC P0443 sets

If you have good electrical knowledge,check and test the circuit,if its ok change the purge solenoid

see the location

my bad.

minibike132 · November 1, 2008

Well you did put on a used solenoid, could be that it is no good.

You have 11.8v on that wire, it should be battery voltage so check to see what that is.

I use a test lamp on these type of circuits because it is possible to have enough voltage but have a poor connection that sucks the necessary amperage to drive the circuit.

As I stated earlier if the positive circuit is ok and the valve is ok then you should probably take it to someone that has the proper equipment and know how.

Good luck.

Mike, First off let me say Thank You, I really appreciate your help.

I did check the battery voltage and it was higher, something like 12.4v or 12.6v.

The solenoid was a "take off" and was spotless, it even had a blue cap on the canister port...looked very factory. You are right though...it could be bad.

I'll rig up a test lamp and see if it flashes (or should it go on fully).

It should be on anytime the key is on. No flashing if you are going directly from the pink wire to ground.

If the wires or connections are bad how do I check that. Continuity check between PCM end and valve end?

You can check continuity with the valve and pcm disconnected just be careful not to stick anything in the pins at the pcm, they spread out very easily and you could create more problems than you started with

I have dealt with PWM solenoids before. I believe the "driver' is a bit of software, correct? If the wires and connections are good, the valve is good, would a replacement PCM solve this? Is it possible to "reset" or reprogram of the PCM?

Yes, if the valve and wiring are good the only thing left is a pcm. It's alot easier to take it to someone with a tech-2 that can activate the system and check system operation but if you want to go the diy route then you have a good handle on what to do.

I have located a company that will program the PCM to my vin number, they are about $100. Is PCM replacement something that the shadetree mechanic can undertake?

Yes, although even if they program the new pcm to your vin there are on vehicle calibrations that need to be done. I think the only thing that needs to be done on yours is a crank variation relearn but you will run fine without it. I'm short on time today so I'll explain what that is when I get a chance.

This is the claim about thier product

******GM installed this 12200411 ECM in all of the above applications. This was possible because each of these models received their specific programming from the factory. In other words, you can't simply swap a used ECM from one vehicle to the next. We are a licensed user of the same GM software that a GM garage would use to reprogram and update your computer. With your purchase we will reprogram the ECM, with the latest software updates available from GM, to your specific vehicle using your VIN (vehicle identification number)

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kennystruck · October 31, 2008

The valve does not operate all of the time. It should have constant power on the pink wire, which is terminal A, any time the key is in the on position. The dark green and white wire is the ground side. That wire goes directly from the valve to the Powertrain Control Module. My suggestion is if you have little experience do not experiment with that side of the circuit. There are ways to check that circuit but it requires either a very expensive multimeter with special functions or a scan tool that has output control functions so that the circuit could be activated.

I would check for power on that pink wire and if you don't have it come back. If you do have power there wait for the new valve you ordered and install it. Your light may not go right off so give it a couple of drives before you go any further.

I have 11.8 VDC on the pink wire.

I cleared the codes again and drove the truck around a bit. After about a minute the code reader gave p0443 again. It took about 8 minutes for the oxygen sensor check to clear. The check engine light did not come back on, but the reader is still displaying p0443 and an "amber" status (it gives a green status when all systems have completed their diagnostics and there are no codes).

7am edit....The check engine light is back on

kennystruck · October 30, 2008

Thanks for the response Mike

I installed the valve yesterday, cleared the code with my code reader, and the damn light came back on within a minute. Then I drove the truck about 10 miles and started/stopped the engine several times and the light has not gone out yet.

I'll check the power on the pink wire to the valve as you recommended and let you know. Should it be 12V? Is there a fuse dedicated to this circuit?

Are there other tests? You mentioned a test lamp previously.

If that does not work I guess I'm off to a shop that has the proper diagnostic tools.

This won't really become an issue until next September when I have to get a California smog certificate to renew the registration. If I could get the code off for 10 minutes I could pass the smog test.

Thanks again,

Ken

kennystruck · October 26, 2008

I tried to find the valve yesterday and it seems I can't get the plastic cover off, the one that says "vortec" on it. I spin the fastener with my 8mm socket but it does not back out. I also tried putting a vice grip on it and spinning it while applying upward pressure, same result. This is right on top of the engine so it does not seem like there's any way there's a nut on the other side I'm supposed to be holding. Maybe I'll just have to mangle the plastic cover to get it off. Any ideas?

If you can't get the cover off just grip it and rip it. What that bolt goes into is a brass nut that is pressed into plastic. If the brass nut starts turning it will never come off the way it is supposed to, you will have to break it and try to fix it once it is off.

I have also looked online for the valve, thinking I might just plan to change it but can't seem to find it. I'm looking under solenoid valve and purge valve for my year truck. Maybe this is a dealer only item?

I can't help you on part numbers but there are people who can and I expect to hear from one of them shortly.

I guess I'm not sure how the test the circuit, I only have an OBD reader and therefore no way to interface to the PCM and command the valve to see what it is doing. If it is not the valve itself, or the connector, does it mean there's a problem with the PCM, this sounds like it might be really expensive.

I can help with the testing once you get the cover off. I need to know if you have a test lamp and a multi-meter. We can test one leg of the circuit with the lamp and the other with an ohm meter but without a scan tool that can activate the circuit we cannot test the PCM. We can however rule out wiring and that is a big hurdle to be able to rule out.

Thanks for the ideas so far...just knowing where the darn thing is will be a help.

Get the cover off and you will see the valve, It might even be unplugged and then you will find the problem solved in a few seconds.

kennystruck · October 26, 2008

OK I got the cover off. The connector is plugged in to the solenoid valve, so not quite that easy.

I started the engine with the valve out, the truck barely ran because of the manifold "leak". I plugged the hole with my finger and it ran fine. Should I have heard the vavle trying to actuate? I heard no "clicking" noise. I replaced the vavle and restarted the truck. There is s small port located on the plastic tube that runs to the vavle. I unscrewed this cap and there was no vacuum there (i.e. the valve was not open)

I do have a decent multimeter that has a cool feature that tests continuity (that should provide the same functionality as the test lamp...but I can rig up a test light if I need to).

I bought a "take off" purge valve on Ebay for $12.99, such a deal. Hopefully I'll get it by the end of the week and that will solve the problem.

Sparkstech, I'd still like to trouble shoot the wiring if you can support that.

Norseman · October 30, 2008

Thanks for the response Mike

I installed the valve yesterday, cleared the code with my code reader, and the damn light came back on within a minute. Then I drove the truck about 10 miles and started/stopped the engine several times and the light has not gone out yet.

I'll check the power on the pink wire to the valve as you recommended and let you know. Should it be 12V? Is there a fuse dedicated to this circuit?

Are there other tests? You mentioned a test lamp previously.

If that does not work I guess I'm off to a shop that has the proper diagnostic tools.

This won't really become an issue until next September when I have to get a California smog certificate to renew the registration. If I could get the code off for 10 minutes I could pass the smog test.

Thanks again,

Ken

Try spraying a little intake cleaner in to your old one and see if that helps.

minibike132 · October 26, 2008

I tried to find the valve yesterday and it seems I can't get the plastic cover off, the one that says "vortec" on it. I spin the fastener with my 8mm socket but it does not back out. I also tried putting a vice grip on it and spinning it while applying upward pressure, same result. This is right on top of the engine so it does not seem like there's any way there's a nut on the other side I'm supposed to be holding. Maybe I'll just have to mangle the plastic cover to get it off. Any ideas?

If you can't get the cover off just grip it and rip it. What that bolt goes into is a brass nut that is pressed into plastic. If the brass nut starts turning it will never come off the way it is supposed to, you will have to break it and try to fix it once it is off.

I have also looked online for the valve, thinking I might just plan to change it but can't seem to find it. I'm looking under solenoid valve and purge valve for my year truck. Maybe this is a dealer only item?

I can't help you on part numbers but there are people who can and I expect to hear from one of them shortly.

I guess I'm not sure how the test the circuit, I only have an OBD reader and therefore no way to interface to the PCM and command the valve to see what it is doing. If it is not the valve itself, or the connector, does it mean there's a problem with the PCM, this sounds like it might be really expensive.

I can help with the testing once you get the cover off. I need to know if you have a test lamp and a multi-meter. We can test one leg of the circuit with the lamp and the other with an ohm meter but without a scan tool that can activate the circuit we cannot test the PCM. We can however rule out wiring and that is a big hurdle to be able to rule out.

Thanks for the ideas so far...just knowing where the darn thing is will be a help.

Get the cover off and you will see the valve, It might even be unplugged and then you will find the problem solved in a few seconds.

kennystruck · October 25, 2008

I tried to find the valve yesterday and it seems I can't get the plastic cover off, the one that says "vortec" on it. I spin the fastener with my 8mm socket but it does not back out. I also tried putting a vice grip on it and spinning it while applying upward pressure, same result. This is right on top of the engine so it does not seem like there's any way there's a nut on the other side I'm supposed to be holding. Maybe I'll just have to mangle the plastic cover to get it off. Any ideas?

I have also looked online for the valve, thinking I might just plan to change it but can't seem to find it. I'm looking under solenoid valve and purge valve for my year truck. Maybe this is a dealer only item?

I guess I'm not sure how the test the circuit, I only have an OBD reader and therefore no way to interface to the PCM and command the valve to see what it is doing. If it is not the valve itself, or the connector, does it mean there's a problem with the PCM, this sounds like it might be really expensive.

Thanks for the ideas so far...just knowing where the darn thing is will be a help.

minibike132 · October 29, 2008

The valve does not operate all of the time. It should have constant power on the pink wire, which is terminal A, any time the key is in the on position. The dark green and white wire is the ground side. That wire goes directly from the valve to the Powertrain Control Module. My suggestion is if you have little experience do not experiment with that side of the circuit. There are ways to check that circuit but it requires either a very expensive multimeter with special functions or a scan tool that has output control functions so that the circuit could be activated.

I would check for power on that pink wire and if you don't have it come back. If you do have power there wait for the new valve you ordered and install it. Your light may not go right off so give it a couple of drives before you go any further.

kennystruck · November 1, 2008

Test light fully lit with key on.

I was going to check continuity on the green with white stripe wire, but there were a zillion wires going into the PCM, with a bunch of green ones and my wires are prety dust covered so it seemed pretty impossible to know which wire to test. Can you tell me which terminal block that green wire goes to?

This continuity check is my last resort before spending the big $.

minibike132 · October 25, 2008

Your link is about canister vent valve,and this DTC is for purge valve solenoid.

Anyway the control module controls the EVAP canister purge valve ON time by grounding the control circuit via an internal switch called a driver. If the control module detects an incorrect voltage for the commanded state of the driver, DTC P0443 sets

If you have good electrical knowledge,check and test the circuit,if its ok change the purge solenoid

see the location

Everything he said ^^^^^^^ I just wanted to add that in the picture the solenoid is what the #1 connector is plugged into.

minibike132 · November 1, 2008

Well you did put on a used solenoid, could be that it is no good.

You have 11.8v on that wire, it should be battery voltage so check to see what that is.

I use a test lamp on these type of circuits because it is possible to have enough voltage but have a poor connection that sucks the necessary amperage to drive the circuit.

As I stated earlier if the positive circuit is ok and the valve is ok then you should probably take it to someone that has the proper equipment and know how.

Good luck.