OBD II codes P0410 and P1411 AGAIN!

[judibake]

Back to the experts again. I bought a 2001 C2 in February. It runs beautifully well.

About 1 month afterwards the CEL goes on and I take it to a well known independent in Toronto whose diagnostics show the above codes. He fiddles under the rear hood and states that a vacuum hose has become disconnected which he puts back to normal, removes the codes and resets the engine. No charge. CEL is off for about 100 miles and then reappears. It's now time for me to look myself. A connecter tube is broken leading from the electrical change-over valve to the air change-over valve. Something that is easy to fix and replace myself. I go back to him to survey the repair and reset the codes to normal. He finds all is well. No charge. 100 miles later on goes the CEL. Frustration. Back again to the expert who now thinks it is the combination air change-over valve /non return valve (2001 and after). $350 total which I thought was reasonable.

Now I purchase a Durometric Diagnostic Tool for myself. 100 miles later the CEL is on again.

Same codes. Here's what I now do. Check one way valve to the air intake system - OK. Check all accessible vacuum lines by accessing them with tubing through which I blow and suck - OK. Remove the electric change over valve and read the voltage in the harness with the SAI pump on and then with the electric change over valve on itself - 8 not 12 volts (the meter is correct). Replace the electric change over valve with a new original part.

The CEL has been reset and I await with trepidation the day that it reappears. Then what?? Should the voltage at the electric valve be 8 volts or 12 as suggested in one article that I read? I don't want to believe that the inlets into the cylinder heads are blocked with carbon deposits. I think that may be unlikely for both banks at the same time and the codes indicate that both banks are involved.

I would appreciate any advice. Of course with the replacement valve the CEL may not come on again. The above may be informative for anyone that has these codes appear for the first time.

Mel Goldberg

Toronto

[DBJoe996]

It will be interesting to see what someone else says. Why do you not want to believe the cylinder head ports are clogged? How many miles do you have? Mine have to be (I figure after 122,000 miles), the Secondary Air Injection CEL pops up all the time and I carry an inexpensive OBDII reader in the console, read the codes (always the same), erase and forget about it. The SAI system is so the car can pass emission testing at startup, and doesn't do anything but pump air into the engine exhaust mix to fool the testing equipment with a diluted mix. I figure my routine is to read/delete the codes when they pop up until one day I have to pull the engine, fix all kinds of stuff and probably tackle this minor issue at that time. Some people have even (gasp!!) removed the bulb from the CEL to stop the annoyance regarding SAI CEL's all the time. Not me...but just saying...

[Loren]