I drove my car in for an emissions control today, and when I got there I heard a loud clicking noise beneath the hood, it sounded like a relay clicking back and forth.. So I told the mechanic to take a look, and he concluded that it was the air pump relay that was clicking on and off.. And sure enough I failed the emissions test quite badly (CO% of 8,5) because of this, as there wasn't enough oxygen going into the exhaust to clean it.. I've tried changing the fuse, but it wasn't blown or anything, so that wasn't the case... any other suggestions as to what this could be, or do I simply have to buy myself a new relay/complete air pump? .. I live in Norway, so any pointers to a good american webshop with international shipping selling these would be appreciated, parts tend to be severely overpriced here, often costing 500-1000% more than in the states (I know, it's sick.. but it's true).

Thanks in advance.

 

Could be the relay, or the wiring. First off, the AC fuse is the fuse for the airpump - it's in the fusebox under the hood. If that's good, unplug the connector to the airpump and use a multimeter on the 2 pins on the wiring harness - one should have 12v even with the car off.

If that's good, then the power circuit is good, and that's half of it. The relay is in the relay box by the hood latch, under the stock plastic airbox duct. I think there's another relay in the box you can swap it out with for testing purposes.

Most airpump problems are the fuse being blown or the wiring to the airpump (close to the grey connector) being VERY damaged from heat.

Dale

 

On my car, as Dale said, the wires on the airpump plug were so brittle that the plastic sheath had come off causing them to short out. Then one of the wires snapped off entirely.

 

Thanks for the quick replies, and I'll be sure to check out the wirings as I've already confirmed that the fuse is working, I know that the AC shares the same fuse so I checked it immediately.

It may be as you say, that one of the wires are brittle because of overheating, but if one of them has come off alltogether, wouldn'd that make the air pump get no power at all, and thus not making the relay even click? .. 'cause it's clicking madly

 

Hrm, if your relay is clicking open and closed quickly/repeatedly it's probably either due to a faulty relay or some thing may be wrong with whatever is driving the relay (I'm guessing the ECU). If you haven't already, try re-seating and cleaning the contacts on the relay to see if that helps. If not, you could try (as Dale suggested) replacing the relay (maybe borrow a relay of identical spec from some other system if possible?) first.

FWIW if you've got a short in the air pump wiring harness, it could be causing too much current to be drawn through the relay which may have resulted in damage or the behavior you're seeing so definitely look into that first.

 

It has been over 12 years, but in case deish somehow gets this message...
Was the cause ever determined?
What was it?

Thanks for any response.