Air pump testing
Thread Starter
Heel & Toe
Joined: Sep 2010
Posts: 18
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Air pump testing
Just purchased a 2000 Convertible. Got a PO410. I do not hear the pump run on start up. I pulled the battery and mount. There was the usual acid signs but not too bad. I did not see any problems with the harness or lines although I did not cut them open to check. Also, I have not gone into relays or fuses yet. Is this a common fail? Anyway, My question is when I remove the pump how do I bench test it. I do not want to eliminate the system. I know it may sound insane but I may take the pump apart if possible to repair it. I like a challenge. Is there a video or pictures showing the pump R&R? Thanks
Le Mans Master
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From: CA.
St. Jude Donor '13-'14-'15
Here is a great site for DTC diagnostics and repair---has a the wiring diagram and testing procedure for the P0410
http://www.gearchatter.com/viewtopic10032.php
http://www.gearchatter.com/viewtopic10032.php
Thread Starter
Heel & Toe
Joined: Sep 2010
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Thanks for that post. I was a Chevy A tech in the 80's and early 90's. I do not have access to a good scanner at this point. Anything I have left from those days is long obsolete.I would like to have it to turn the pump up etc.through the scanner. Has anyone pulled a pump out and tested it on the bench? Since I don't have it out yet I have not had a chance to look at it.
Team Owner
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Thanks for that post. I was a Chevy A tech in the 80's and early 90's. I do not have access to a good scanner at this point. Anything I have left from those days is long obsolete.I would like to have it to turn the pump up etc.through the scanner. Has anyone pulled a pump out and tested it on the bench? Since I don't have it out yet I have not had a chance to look at it.
The new one (new AC Delco) is MUCH quieter, as it should be.
Post up your results if you do disassemble one and post up some pics too if you can.
Thread Starter
Heel & Toe
Joined: Sep 2010
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onward
Pulled the pump-took all of 5 minutes. Very easy to test. I thought it might have a multiple pin connector but it had just two. Jumped it off the battery and it ran strong and quiet with good output. I swapped the maxi fuse and removed and installed it multiple times to clean the contacts. I also swapped the relay with a known working one from the fog lamps. I erased the code. Now when I start it I can hear the pump run ( I think ). The issue is that this pump is so quiet compared to the turbine sounding one in my prior C5 that it was hard to hear. This car only has 18K miles and it only went 4k in the last 4 years. I am hoping this cleared it up. I will post again after I do some miles.
Thread Starter
Heel & Toe
Joined: Sep 2010
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Erased the code and took a ride. PO410 again after about 7 miles. Why does this take so long to come on if the pump only runs on start up? I also get a cat not ready message on the scanner. I can hear the pump running on start up. Should I go to the check valve? Has anybody seen these fail? What method to test it? I only see the obvious one on the drivers side. Is there another? Any other ideas would be great. Thanks.
OK, Answered my own stupid question. Check valves will set a code. Again, any help is much appreciated.
OK, Answered my own stupid question. Check valves will set a code. Again, any help is much appreciated.
Last edited by 99tripleblackc5conv; Jun 10, 2012 at 10:29 AM.
Race Director
Joined: Apr 2007
Posts: 11,150
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From: South Western Ontario
There is a vacuum operated valve on the output of the pump. Pull the hose apart at the coupler by the washer fluid resevoir and see if air comes out when you first start it to test if this valve is opening.
I would guess that a stuck closed check valve is detected when the computer operates the pump and finds that only one bank gets air to the O2 sensor. If this is true then it's possible both chevk valves are stuck closed and the computer operated the pump and detected no air so it threw the pump code.
I would guess that a stuck closed check valve is detected when the computer operates the pump and finds that only one bank gets air to the O2 sensor. If this is true then it's possible both chevk valves are stuck closed and the computer operated the pump and detected no air so it threw the pump code.
Thread Starter
Heel & Toe
Joined: Sep 2010
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I do not see a vac line by the washer reservoir. Can you be more specific. I see the vac line off that valve and it seems to go towards the passenger side. The pump runs on start up. I took the pump out and bench tested it. The output was very strong. Now with it back in the car I disconnected the hose at the D/S check valve. The air flow was very weak at the valve on start up. Does the valve on the pump regulate air flow amount? If so, where does the vac source originate and is constant or switched? If switched, what controls it. Is the airflow at the check valve supposed to be strong, has anyone felt it on their C5?
OK, Remember my brain is a little rusty. I applied vacuum to that valve with a hand held pump. Luckily I did not sell all of my tools. With vacuum applied the air flow is very strong at the valve. I think I am getting closer. Whoopie. So my question now again is where does the vac originate, is it constant and if not what controls it. Thanks so much so far guys.
OK, Remember my brain is a little rusty. I applied vacuum to that valve with a hand held pump. Luckily I did not sell all of my tools. With vacuum applied the air flow is very strong at the valve. I think I am getting closer. Whoopie. So my question now again is where does the vac originate, is it constant and if not what controls it. Thanks so much so far guys.
Last edited by 99tripleblackc5conv; Jun 10, 2012 at 11:25 AM.
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Race Director
Joined: Apr 2007
Posts: 11,150
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From: South Western Ontario
I was referring to the air pump output hose you have just checked. There is a vacuum hose running to a valve down by the pump. As far as I know, it just turns on with the pump. There is a solenoid valve that controls it. I can't tell you where it is. The vacuum hose does pass under the battery inside one of the harnesses and maybe it's got a hole in it from battery acid which would be the most likely cause for this failure. A C5 Tech forum search for "vacuum hose P4010 check valve" or something similar should lead to a thread with more info.
Thread Starter
Heel & Toe
Joined: Sep 2010
Posts: 18
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Took the access panel out of the wheel well and removed the plastic piece from the cove. Stuck my hand in and came out with 2 pieces of hose. Cut it back to an undamaged area and joined it with some vac hose. 30 miles so far and no MIL. I am hoping for the best. Thanks again for every ones help.
Thread Starter
Heel & Toe
Joined: Sep 2010
Posts: 18
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Back again. No vacuum at the pump. I pulled the solenoid down. No vac there. Went back to the tee. Good and bad news. When I first started the repair I stuck my hand in and found 2 pieces of line. I joined them with a hose and thought that was it. When I look at the tee I can see that each end of that hose goes to opposite sides of the tee. That ain't gonna work. I can't see any other broken pieces of line in there. Where does the vac originate for the tee. Is it in the big harness behind the battery? Also, I can't see where the line passes thru the firewall for the a/c. Hoping I can repair this with the fender on.
Which side of the tee should the vac source be connected to.
Which side of the tee should the vac source be connected to.
Thread Starter
Heel & Toe
Joined: Sep 2010
Posts: 18
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Out working on it now. Answered my first question. Found the broken line in the harness. last 2 questions. Where is does the a/c line go thru and which side of the tee gets vac. With check valve or not.
Thread Starter
Heel & Toe
Joined: Sep 2010
Posts: 18
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Success. Put it all back together and got a nice strong flow from the pump on start up. Cars seems to run a little better without the open vacuum leak as well. One can only imagine what this would have cost if I took it somewhere. And if they could have even fixed it. Anyway, Thanks for everyone's help and patience.