I've been attempting to diagnose CEL issue (and codes) for a couple weeks now. Full story - all codes - parts replaced - can be read at

http://www.peachparts.com/shopforum/showthread.php?t=220910

But, I just have a quick question or two about the secondary air injection pump. I'm trying to figure out if the pump is defective, or simply not being turned on/activated.

At cold start:

1. If pump runs...you can tell this by looking at the triangular plate in the front, correct? (the clutch engages inside the otherwise free-wheeling pulley) (is this possibly the dumbest question ever asked on here? LOL!)

2. If pump is defective and not running...wouldn't you still get voltage reading at the harness connection to the pump? And wouldn't it be 12 volts, more or less?

3. If you don't get voltage at the harness...is it possible there is a relay not operating? (in other words - the pump might be ok, but it is simply not getting energized)

4. Finally, can I test the pump directly by using another 12 volt source and connecting it to the pump?

If anyone can answer advise me on this....I'd greatly appreciate it. I'm obviously trying to figure out if it is the pump itself that is bad before I buy the replacement. Or, if it the problem is really that the pump is not getting turned.

By the way, the reason I'm focusing on this issue is that after reading codes for week, I've figured out that that first two codes that return (meaning, before any lambda or knock codes) are the following two:

Pin 4 - Code 11 = secondary air injection system, open or short circuit
Pin 19 - Code 4 - air injection system faulty

Oh...and also by the way - I've just put a new 02 sensor in.

Thanks!

Jim

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Syntax26

1995 MB E420 (lowered)
1989 MB 300SE (sold to brother)
1975 MB 280 (sold)
One damn fine jacked-up golf cart