10-PCM P0410HC Air System-B fault

[mdevese]

My 2002 C5 has recently developed a 10-PCM P0410HC Air System-B fault. The engine check light came on. I got into the DIC codes, it actualy loads I wrote them all down and the deleted all codes. Since then the PCM 0410 has returned. I have had a look and taken the battery out, remade the three earth connection just below the battery. gave it a bit of a clean under the battery and put it all back together. I went to work the next day and within 30 miles the PCM 0410 was back, then after another 10 miles the engine check light came on again.

Can anyone out there give me a clue how to fix this, before I take to the dealer?

 

[c4c5specialist]

HI there,
There would be a few things to check.
First, when you start the engine cold, check near the left front headlamp to listen for a humming noise coming from the area.
That would be your air pump running.
If you hear that, it will most likely be your air injection solenoid or the check valves themselves.
Let us know if you hear the humming noise and it will only be on a cold start that you will hear it.
Allthebest, c4c5

 

[mdevese]

Hi thanks for the reply.

I have checked for the humming from the left headlight, and I think I heard it? The car was in my garage and you know how noisy an LS1 is and it was in the middle of the day in Texas! Can you give me a clue where the solenoid is and where the check valves are.

Also here is some more info to go on. recently it had a side colission while parked, new drivers door skin fitted, sill, and rear fender repaired. Rear fender repaired taken off as well as frony and rear bumbers and the front fender aligned with the new door. After the repair I found the washer tank loose.

Do you think this has anything to do with the fault?

 

[mdevese]

Hi Also I have recently had to put a new battery on as the previous one died. This was the reason for a lot of the DIC codes.

 

[c4c5specialist]

HI there,
The air injection solenoid is under the drivers side headlight.
You will have to get underneath the vehicle, and remove the black closeout panel to access it.
You can get to the drivers side check valve, which is bolted to the exhaust manifold very easily.
The passenger side check valve is located behind the intake manifold, so it is going to be tough to get to.
If the window washer was loose, check the black 5/8 inch rubber hose going under the master cylinder and going to the exhaust manifold, make sure its attached.
Allthebest, c4c5

 

[mdevese]

Hi There,
Thanks again, I found the check valves, and yeah the passenger one is hard to see.
The 5/8 inch rubber hose is connected as far as I can see to under the left head light to the tee that branches left and right, all the hoses and pipes connecting to both sides look fine to me. I'll have to check the relay now, thanks for the info as to where it is.
It's a shame you live and work so far east (nearly 1700 miles for Dallas) other wise I'd bring it to you to fix it for me.

 

[c4c5specialist]

HI there,
YOur next course of action, is to disconnect that 5/8 hose and then start the car COLD.
See if there is a good stream of air coming OUT of that hose.
Allthebest, c4c5

 

[David-F]

You said the previous owner had the battery replaced I suspect it was replaced for leaking acid I suspect you have a problem with vacuum lines under the battery there are three vac. lines that run under the battery tray one coming from the back of the intake over to the vac. canister(behind the right fender infront of the right rood) one from the canister to the harness going into the car(for the mode door operation in the HVAC) and one goint to a solenoid in the upper fender that then goes to the air valve on the air inject pump under the left front head light. If acid gets on any or all of those vacuum lines it will eat them up or put holes in them and you can loose vacuum to either the A/C and air will only come out to the windshild or loose vacuum to the air inject pump and set that code. Tou will have to remove the battery and have a look around, if you start to see white spots on any of the lines you will have to looking real close I'm sure you are going to find something.

David Fulcher

 

[mdevese]

Hi c4c5 specialist, I disconnected the 5/8 inch pipe by the washer tank and started the engine, I felt the air blowing form the air pump but not what I think is a good stream though. I blocked it with a finger and the air pressure built up. I also thought that if the check valves are OK then no air should come form the other side, but no I felt air pulsing form the exhaust side. Does this mean I have a faulty check valve and everything else is OK? Or what?

Michael.

 

[mdevese]

Hi David,
Funny you should mention that bad vacuum hoses mean air blows on the windshield, the A/C control don't see, to work to switch air form face to windshield, I get face and winshield all the time. It doesn't matter what I select. But after reading your posting I removed the battery again to look at what you said but could not see any pipes. Are they under the tray the bttery sits on? If so the bolts that would remove it the one that is on the fuse box side has the captive nut come loose. So all it does is spin. Any suggestions?

Michael.

 

[David-F]

Yes you will have to remove the battery tray and from the sounds of it you do have acid damange. The nuts for the bolts the hold the battery tray down are a type of wire nut that clip onto the tray. If the bolt is spinnig and not loosening that can be a problem I just don't know if you would be able to get behind there to hold the nut but what you can try to do is use a good screw driver and wedge it inbetween the tray and frame and pray the tray and frame apart from each other it's possible you might put enough force to add enough friction on the nut to hold it and loosen up. If not you might get enough room to get a hack saw blade down there and cut the bolt. Good luck it will take some time but you will need to get that tray out of the way inorder to repair the lines.

David Fulcher

 

[c4c5specialist]

Hi there,
If you have air pressure to that point, most likely your air injection check valves are rusted shut.
You will be able to STOP the air flow by putting your thumb over it.
Allthebest, c4c5

 

[David-F]

There will be very little air flow from the air pump and seeing how you are feeling pulsing from the other hose is a good sign that the check valves are working(at least one of them) which means if one was restricted a P1415 ot P1416 would have set. Again your problem is vacuumn and has to be repaired first then you can clear the codes and recheck the car.

David Fulcher

 

[mdevese]

Hi c4c5 specialist,
I have taken the left check valve off and blown through it both ways, the rubber tube side (into the manifold) air passes, the threaded side (manifold side that should be closed when blown) air did not pass by mouth. While I had it apart I disconnected the 5/8 tube by the washer tank, started the engine blocked the pipe and had air pulsing from the tube that would go onto the check valve I had just removed. Does this mean that the check valve behid the engine that goes to the right bank is faulty?

Michael.

 

[mdevese]

Hi David,
I cut the rotating bolt to remove the battery tray. Got the tray out but I could net see any vacuum hoses underneath. There was one fat rubber hose but that looked kiet the drain hose from the botton of the windshield. All I saw was a bunch of cables in looms and the PCM module. I have indentified what I think are the heater and A/C pipe work circuits. How big are the are the vacuum pipes you are talking about. I still have no control over the vent system in the car.

Michael.

 

[mdevese]

Thanks to all for help so far.

Michael.

 

[David-F]

The tubes is only about a 3/16" thick if you find the harness assembly that leads into the fire wall just put your hand around the harness and start working your way away from the fire wall about 3 or 4" away you should find the tube coming out from the harness it should come out and loop down and back into the lower fender towards the front of the pas. door.
Now if you look twards the fire wall directly behind the battery you will see two wire harness going over twards the engine one thicker then the other. The thickest one is the one you need to look at that comes off the engine and that is the harness in which the vacuumn tube that hooks to the rear of the intake and supplies vaccumn to the canister in the right inner fender. Now like you did wiith the harness coming from the firewall start tracing that harness from were it comes through that plastic shield that keeps the heat off the battery you will find the the harness "Ys" it's around this "Y" that the tube should come out one part of the "Y" goes down to the ECM the other to connectors to the out side of the battery.
The other tube you will find going from the canisterin the lower rear of the fender to the upper part of the fender above the tire and that is were you will find a solenoid.
If for some reason you are unable to find these then there is a good chance that they have been compleatly eaten away and you will have to open the harness and find a park of the tubes that may still be good. Now there have been cases were the acid has eaten the tubing all the way to the intake but not very offten but there are many times that except for down around the cansiter in the harness there is nothing left.
Also as I stated before and as you have confirmed the check valves are working again your problem is vacuumn that has to be repaired first.

David Fulcher

 

[David-F]

Let me just add a little bit here once you have found the tubes and cut out the bad sections and found some small rubber vacuumn hose that will slide over the tubes and reconnected the tubes just lay the battery in the car and hook it up and start the car and check it's operation. For two reasons first there may additional holes in the tubing you may have missed and two if enough of the tubing is missing it can be almost imposibable to figure out which tubes to which tube so you may have to switch the two and recheck there is a check valve on the one that will keep it from working if hooked up bacwards.

David Fulcher

 

[mdevese]

Hi David,
Thanks, great detail. I'll strip it down again tomorrow and let you know what I find. Things are tight to work on on a C5 aren't they!

Michael.

 

[mdevese]

Hi David, I found one pipe with holes in it so cut out the bad and patched new pipe. Another one had a small hole that I taped up, but I could not find the third pipe. The A/C is working better now but still blows all the time on the windshield and in the mornings is cools the air hitting the windshield and ices up the outside (even in Texas). Any suggestions.

Michael.