p911guy

I keep getting a CEL for a P0410 - Secondary Air Injection Malfunction. The 40AMP fuse blew, so I replaced it and reset it which lasted an hour or so. Replaced the relay (and fuse again!) and it lasted a couple of days before throwing a CEL again. The fan does run, but won't shut off. Any ideas?

Zeppelin

I suppose the fan (pump) motor could be partially shorted causing it to draw more than 40A. I would pop the plastic cover off the old relay and see if the contacts are melted like mine were after 30K miles or so. If they are not melted then the relay was never bad and it is probably the motor.

You could also try running the motor directly off the battery with maybe a 40Amp fuse in line to see if it blows. If so the air pump is bad and would need to be replaced.

p911guy

The relay looked in good shape, but prior to replacing the relay, the pump wouldn't start at all. Since replacing, it won't shut off once started until the car's turned off. Totally weird. Thanks for the feedback though as it gives me an idea on how to go about pricing it out at a service place. I noticed your location is OC. Where do you take your car when it needs "beyond basic technical skills"?

mikekuriger

funny you should mention this, mine just threw the same code today. I assumed my pump was bad since it's been whining for like 2 years now. Maybe mine is a bad relay / fuse as well. I guess I'll have to check.

thanks!

Zeppelin

I have never had to take mine anywhere as any issues so far have been small. So for a issue like this I would not take it anywhere as no matter what the issue they will say it is the air pump and just start replacing parts until you are broke.

The air pump motor can't run without power so if it will not shut off it is not the air pump. Either the new relay is sticking or whatever controls the relay is wrong. I say put the old relay back in and see what happens then.

Mark.D

I've replaced 4 of these on my C55. Crappy unit. last time I had to replace the wiring harness and fuse. Its a spendy replacement.

mikekuriger

where is the relay and fuse located for the air pump?

430

I feel your pain. I am fighting a P0410 error myself. Replaced the pump with no luck. The pump kicks in but never drops the values to the level needed to prevent a CEL.