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Hi all, my name is Jack, new member, just joined last night. I am also a first time corvette owner with a 2003 coupe. I have googled till I am blue in the face and have been unable to find an answer to my questions. I've seen the very question asked but not answered.
Here is my situation.
I just purchased this car a little more than 2 weeks ago. I had driven it for 2 weeks and put several hundred miles on it. The only problem I found with it was the oil pressure gauge pegged at 80 and 130 on the DIC.. I researched and immediately came to the conclusion was the sending unit as it was the overwhelming response. I did not want to tackle the job so I had a local reputable repair shop do it. They called back shortly after I dropped it off and said they would have to remove the intake. I had expected they would choose to go that route, no problem. A short time later they called and informed me the pcv pipe was deteriorated and needed to be replaced and it is a dealer only item so it would be the next day before they completed the job. Again, no big deal. I pick the car up late the next day and drive straight home @ 5 miles.and just park it over night. Next morning I am driving into town and approx. 3 miles in the CEL comes on. so I go home. The car sits for a few hours and curiousity got the best of me so I checked the codes with a small pocket scanner I have and i get p0410.. Then I started the car and it was pretty hot outside by this time and the AC came on and did its usual high speed when I lowered to temp setting to 60 to cool off quickly. It ran high for a few secs then I could no longer feel the air rushing thru the vents anymore but the fan was still on high. It feels kike the vent doors are not opened all the way. I believe they are operated by vacuum from what I've read.
I have gone back to the repair shop and explained everything to the tech and he said its probably a coincidence (I tend to think not), and that he is swamped this week and could not do anything until next Monday and that it was ok to drive it the way it is, which I've also read.
My questions are, first of all, is it probable the code is connected to the removal of the intake? If so what is the likely problem?
Second, is it possible the ac vent situation could be also related? Or is it more likely that that part is a coincidence? I only wonder if the two could be connected is because of the possibility of a vacuum malfunction.
Sorry to be so needy my first time out, I promise to not be after this.
I changed the pressure sender myself and ran into a similar problem.
For me after I did the change the air was only coming out the leg vents or the defrost vents (sorry I don't remember which it was) and no matter what I did I couldn't change it. I don't remember if I threw a code, I want to say I did, but I'm not 100%.
Turns out there is a small vacuum hose behind the intake that connects to another vacuum port. It's VERY easy to accidentally undo and not reconnect. I missed this when I did the reassembly and had to just undo my intake afterwards, slide it forward, and reconnect this line. Took me all of 10 minutes to fix. I'll see if I can find a video that shows this line better but here is a picture of the area that it would be in, basically right next to the blue topped connector and about the size of the small rubber hoses near it
.
Left is the front of the engine/car and this on the driver side of the car.
9 out of 10 chance that the shop did not reconnect the small vacuum line to the intake when reassembling. That would cause the symptoms you are seeing. P0410 is for the Secondary Air injection system that is used on cold starts. The system has a vacuum controlled valve that is not opening due to no vacuum being present. The ventilation diverter that control which vent air is coming out of is also vacuum controlled. this small vacuum line provides vacuum for both systems.
Most guys put a short extension onto the line when reassembling to make it easier to reconnect. I have done this on every one I have pulled.
The line is a black hard plastic about 1/8" in diameter. It connects into an rubber elbow. What I do is get a length of flexible vacuum line about 5 to 6 inches long that has a slightly smaller ID than the OD of the hard plastic line. I use this flexible line to replace the elbow and then slip it over the hard line.
To fix this the intake will have to partially come back out to get the line hooked up or put in the suggested extension.
What the P0410 code means:
P0410 is an OBD-II generic code that the engine control module (ECM) detected the engine O2 sensor did not detect an increase in the O2 level in the exhaust when the air injection system was commanded on during an active test. Since you only have a handheld scanner you can't command valve to open as with a bi-directional scanner.
Since your local "reputable" shop had the intake manifold off I'd start there checking the drivers side Secondary AIR system hoses and connections (easy) and the passengers side system (difficult which sits behind the intake manifold...maybe a vacuum line back there might be loose or disconnected causing your AC problem !!
Thank you 8vette7 for your quick reply. First question regarding ac is it is the dual zone automatic. Thank you for the valuable info regarding codes. I went thru the the complete program and only codes are 10pcm p0410HC and p0442HC. Everything else stated no codes.
The HVAC Vent issue is SIMPLE... The Tech either FAILED to reconnect the little vacuum hose to the back of the intake manifold MAP Sensor Nipple OR He connected it and it popped back off. OR the Nylon/Plastic vacuum line CRACKED during the repair.
Either way, it is RELATED to the repair that was done to the car. DO NOT let them bamboosel you!!
All of the VENTS are vacuum actuator controlled. The HVAC System gets the vacuum supply for the vents from the back of the intake manifold from a very small nylon vent line that has a rubber nipple on it.
The nipple is connected to a fitting on the back of the manifolds MAP sensor housing. Its VERY short and difficult to reconnect properly.
You can get a mirror and flashlight and look to see if it just disconnected. Good luck getting it back on without manifold removal and sliding it forward to gain access to the area!!
Thanks everyone. You guys are great!!!!
Im not up to getting into this car and working on stuff I know nothing about. It’s not the old school carburetor, points and condenser distributor vehicle that I worked on in my younger days. That is why I chose to pay a shop to do the work.
With the information you all have given me, I feel much better and will look to see if I can see anything back there. If not I at least have solid information to take back to the repair shop to point out to the area to focus on. Will let you all know how it works out. Thanks again!
You will avoid a lot of headaches and problems if you can find a shop that is experienced with C5. There are a lot of things reputable mechanics don't know about these cars. That vacuum line is just one of them.
Not to change the subject, but when I had my intake off, I extended that vacuum hose about 4 inches. What a difference that made with reinstallation. Just make sure it's routed as to not allow it to kink.
Not to change the subject, but when I had my intake off, I extended that vacuum hose about 4 inches. What a difference that made with reinstallation. Just make sure it's routed as to not allow it to kink.
LMAO... I did the exact same thing!! It came in handy when I switch the intake to a fast 90 as the nipple for engine vacuum is on the passengers side of the intake and the extension reached just fine..
CUT and SPLICE:
Hope this helps you see how you can extend the line...
Quick update. When I checked for codes yesterday thru the DIC, I also erased them and car sat all night. Late this morning I went out with a flashlight and pulled side covers off to try to look behind intake. I did not see any hoses unplugged. I could barely see the part of the MAP sensor where the vac line hooks up but it appeared the elbow is attached. Can’t see any further. Drove the car to do some errands driving @40 miles over a 2-3 hr span. The CEL never reappeared. The hvac vents do not work but if it means anything, the cruise control does work. Does that not also work off vacuum?
thanks!
Quick update. When I checked for codes yesterday thru the DIC, I also erased them and car sat all night. Late this morning I went out with a flashlight and pulled side covers off to try to look behind intake. I did not see any hoses unplugged. I could barely see the part of the MAP sensor where the vac line hooks up but it appeared the elbow is attached. Can’t see any further. Drove the car to do some errands driving @40 miles over a 2-3 hr span. The CEL never reappeared. The hvac vents do not work but if it means anything, the cruise control does work. Does that not also work off vacuum?
thanks!
Originally Posted by Bill Curlee
Good thinking BUT,, NO the Cruise is ALL ELECTRONIC and controlled through the Throttle Actuation Control (TAC) Module.
Monday update. Brought the car back in the shop first thing this morning. Explained to the tech what I had learned from all of you on this forum. Suggested he check for vacuum leak. They delivered the car back to me in less than 1.5 hrs fixed. He found a crack in the line that goes to the map sensor, repaired it and somehow got it back on. All is well and working properly again.
Monday update. Brought the car back in the shop first thing this morning. Explained to the tech what I had learned from all of you on this forum. Suggested he check for vacuum leak. They delivered the car back to me in less than 1.5 hrs fixed. He found a crack in the line that goes to the map sensor, repaired it and somehow got it back on. All is well and working properly again.
Thanks again for for all your help!
jack
He attached the vacuum line he neglected the first time.
He attached the vacuum line he neglected the first time.
Ha ha, could be! The important part is he fixed it, realized it was his screw up and didn’t make any excuses and there was no charge!
Of of course the underlying thing is that I’m retired but working part time delivering for O’Reilly’s Auto Parts. I could help them or I could hurt them. He did the right thing and for that I respect him.
In my short time as an owner, I've come to discover that the C5 has many, many peculiarities. You will have to become the master of them, which likely means you will have to learn much more than any mechanic that doesn't specialize in Corvettes knows. YOU will have to be the expert.
Give them lots of pics, a website with the procedure, and any other info. They will eventually thank you for it.
04-19-2018, 02:49 PM
First time corvette owner with questions
It came in handy when I switch the intake to a fast 90 as the nipple for engine vacuum is on the passengers side of the intake and the extension reached just fine.. 
He attached the vacuum line he neglected the first time.
