Many many moons ago, I threw a CEL that turned out to be P0410 (Secondary Air Injection System). The air pump doesn't turn on when the engine is cold, so somethings definitely up.

Now that I've taken some time to track down the problem, I can't seem to find the components mentioned in the service manual (CD version, not print). I've checked the fuse under the hood, that's OK.

Several steps are for testing the pump's current sensor... at the current pulled by a pump, I'm sure it's just a thick piece of wire (often times a flat bar) measured at both ends, but I don't know where it is. Can anyone suggest where I should be looking for the sensor and what it looks like?

I jumped ahead to check some of the other things. It looks like the manual labels the incorrect connector, but I cannot be sure. It points to the large connector that connects directly to the lower part of the air pump (from somewhere inside the engine bay) and labels it as the (large) air pump relay... I believe that is incorrect. I believe the (large) air pump relay connector connects to the thick 3" wires coming out of the top of the relay module. So, I'm not sure what points should have voltage at them.

Suggestions (or correct instructions) would be appreciated...

I'll add more detail as I muddle through it all...

 

I did the Air Pump Relay Test. Simple enough... if power is applied to the small connector, the large connector should have continuity between the pins.

I do not get continuity at the large connector when the power (small) connector is plugged in). However, I only get 6V at the power connector, and this doesn't sound correct.

Can someone confirm/deny that only 6V should appear at the (small) power connector for the relay? If 6V is the correct value, then the relay is faulty and needs to be replaced (it does say 12V on the side of the relay, soooo.......).

I should add... the engine is still a bit warm, so I'll rerun the relay test later tonight. Unless the engine temp effects the voltage at the power terminals, though, I can't imagine a different result.

 

I just checked the (small) connector for the air pump relay, the portion coming from the engine bay. It still shows roughly 6V (although it's at 5.85V, about 0.20V lower than last night). This is with the engine completely cooled.

 

I cannot be 100% sure, but I believe I have narrowed down at least one problem... looks like the pump itself is FUBARed. Disregarding all of the other tests, I checked the two large connectors that go directly to the pump (took me a while to figure out which wire went where).

+12V comes in by way of the white/red wire, runs through the relay, and into the white/green wire. I bypassed the relay with a jumper wire. Power now goes from the white/green wire into the pump, then back out to a black wire. I check for continuity of the black wire to ground (OK), continuity of the white/green wire from one connector to the second, and power at the white/red.

With a simple pass-through of power, the pump still fails to turn on.

Of course, this still leaves the mystery of the pump's relay. Powered or not, the relay doesn't engage (no continuity). However, this is only checked by way of the 6V power coming in, which I believe is incorrect itself. But I'll tackle that problem when I have a working pump, I suppose...

Any and all advice welcome...

 

Have you resolved this? I get same thing. on small connector, I get ~6v. So checked battery (Sears diehard), it was 6V. the manual does say check to see if it has "battery voltage". So I think it's normal. however, one of the bigger connector from chasis does emit 12V. but no continuity in big connector from air pump relay. I'm trying to replace the air pump relay. if it does work, I'll keep you posted.

 

I'll be swapping out the pump for another this weekend (if scheduling holds true). I'll let you know if it solves the problem...