I have a Volvo 850 GLT 1996. So my check engine light went on awhile back and it was the Secondary Air Injection System PO140. So I replace the air pump and tested the air pump to see that it is working. I tested the SAS Check valve and it is working. I just replaced the air pump relay and the pump is still not coming on. The only thing I can think is that the relay is not switching on, what would cause this? I pulled off the cover to the fuse panel by the firewall and see some relays, but I can't find a specific fuse for the relay. Is there a fuse I need to check in a place other than the fuse box under the hood?
I appreciate any help.

 

The air pump only comes on when the car is really cold.
Are you testing cold?

 

My '94 T5 didn't have the air pump set-up so I have absolutely no knowledge on the system. And I could not locate the relay for the SAS. Wait for other members' replies.


JPN

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I've tested the pump and know it works. I've tested the relay and know it works. I've tested the SAS valve and know it works. The valve opens and the air pump doesn't come on to pump air into the exhaust. On the relay there are three wires: one wire turns hot when the ignition is switched on, one wire is power for the air pump, and the other wire is a switched ground wire. The switched ground wire never gets grounded and the relay never switches and the air pump never turns on. I don't know where the switched ground wire goes, but if I knew I'd be closer to the answer.
Thanks again for any help

 

The ECM switches the ground when the coolant temp is below a certain temp. That is what makes the air pump come on.

 

I really need a wiring diagram. I specifically need to know what wires come out of the ECM.