JakeRobb

SES light came on; three codes:
P0171, P0174, P1416

The first two are "System Too Lean", bank 1 and bank 2, respectively. The diagnostic instructions for those two codes say that if any other codes are present, diagnose those first.

So, I move on to the diagnostic instructions for P1416. The description for this code is "AIR System Bank 2".

Interestingly, the conditions for setting the code require that P0171/P0174 are NOT set; I assume that means that P1416 came up first.

I don't have a scan tool, and so I am unable to perform the first step, which wants me to check the voltage coming out of the O2 sensor when the AIR system is turned on.

The next step says to inspect the AIR system for leaks or obstructions. That I can do. Running my fingers along the passenger side AIR pipe, it feels partially kinked to me. It's hard to tell for sure, because it's covered in heat shroud. I don't have a wrench big enough to remove the pipe (my digital caliper says it's 25mm).

Anyway, if a couple people could check their passenger side AIR pipes and let me know if they feel a similar kink, I'd appreciate it. If anyone has any further advice, let me know. I intend to buy a scan tool and a 25mm wrench so that I can investigate further.

Pics and diagrams to make clear what I'm talking about will be coming shortly.

JakeRobb

Item #7 in this diagram:

2001NBMZ28

P1416 99% of the time is a clogged air check valve, not the 02. The air pipe on mine is bent/kinked too. You're running lean with 171/174 at the same time, could be something else, but I'd look at the PCV/hoses first.

JakeRobb

And a couple photos:

2001NBMZ28

Mine is only bent by the #2 coil, not towards the dipstick like yours appears to be in the pic.

JakeRobb

Thanks. I found this thread on CorvetteForum:
http://forums.corvetteforum.com/c5-t...eck-valve.html

Seems relevant. The basic idea they have there is that I should pull the hose off where it splits into the two banks, spray some carb cleaner in there, and then chase it with some compressed air to make sure it reaches the check valves. Are there any F-body-specific differences I should be aware of?

rv93

mine looks like yours, but if you feel through the sleeve, the diameter of the pipe seems to remain roughly constant.

Marc 85Z28

Just replace the check valve. The most testing you should be doing on thi system is verifying airflow to the valve with the air pump running. No need to monitor O2 sensors. You're best bet is to unbolt the pipe from the manifold, disconnect the hose from the valve, and remove the valve and pipe as an assembly. The valve will need penetrating oil and LOTS OF HEAT to break it loose. A vice will help tremendously.

For the lean codes, remove and inspect all PCV hoses. You'll probably find the hose that runs behind the intake has rotted away.

2001NBMZ28

Agree, just replace the check valve, they're not expensive. If you remove the pipe from the manifold you might destroy the gasket, they're cheap also (GM PN 12553617).

Lean codes aren't related, look at the PVC/hoses or another source of a vacuum leak.

JakeRobb

Thanks guys!

I removed the AIR pipe, cleaned it, reinstalled it, and cleared the codes. The lean codes came back, but P1416 didn't. Now to take a look at the PCV system...