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2002 s10 4cyl secondary air injection pump/diverter valve

I recently pulled my CEL codes and it was secondary air injection malfunction. I could get the code if you want but I would have to go over and borrow my buddies code reader.

Anyway I went and bugged my mechanic friend to use his expensive scan tool and was able to command the pump on and it is working fine. On the top drivers side of the pump is a vacuum solenoid for the diverter valve. It would appear this is the problem.

When I tried to test the solenoid I found out that both of the wires going to the harness were grounded (done via test light.) So I’m pretty sure the wiring to the solenoid is the problem, but my factory service manuel has no wiring diagram to verify this.

I was wondering if anyone could post the diagram or tell me if both of these wires should be grounded. It is my understanding that one of these wires should always be hot. I can post the pics in my manuel if that would make this description make more sense.

P.S. If I need to clarify anything don’t hesitate to ask. Thanks in advance.


I was pleased to find out today that my local library has a subscription to ALLDATA. I was, however, dismayed to realize how hard it was to navigate. Not impossible, just a pain. I did however find what I needed. It seems, however, that all it has is the factory manuel (along with estimated time and flat rate time, I found that interesting.) If I had been less lazy I probably could have found the diagram (A parts location diagram was all they had) in the book I already have.

At any rate, I traced it to the splice pack on the front passengers side of the core support. I will get more involved this weekend. Wish me luck. I’ll let you know if I need further assistance.

Thanks again.

FYI I recently posted looking for a TCM wiring diagram for a '95 Caravan - not so easy to find. I ended up getting one through Mitchell1 service ( - not unlike Alldata (it is a division of Snap-On).

The wiring diagrams are good and complete. The diagnostic info is pretty bare bones but good.

I gave them $10.50 for a week’s access tho I can get the year for $30.

For the $10.50 it was only slightly more than the gas would have cost me to make it to my “local” library (which just isn’t very local).

I’m glad I did it.

I had the luxury of walking to the local library. Glad you found what you needed though. I hope all goes well with your repair as with mine.