SES Code-PO418 - Air Pump - Help?

[x10-wakerider]

My SES light has been on for awhile and the code is "PO418-Secondary Air Injection System Relay Circuit Malfunction." I have replaced the fuse and I just put in a new smog pump, so what now?

Thanks in advance!

[pajeff02]

The secondary air system is easy to check -- it is only activated upon cold start up for a short time to help the cats come up to operating temp sooner. First thing is to pull the air hose that runs over top of the driver side fender well. There should be a union about midway where you can separate the hose. With the engine cold, start the car and check to see if there is air blowing from the hose. If not, it is a blower motor, relay, or fuse issue.

Assuming you have air blowing, the next check is to pull the hose from each check valve. Of course, re-connect the hose over the fender well first. Again, with the engine cold, start the car and check to see if air is blowing from each hose. If not, you have an issue with the electrical vacuum solenoid or diverter valve that is located on top of the engine, driver side, towards the rear.

If you have air at the check valves, the next thing to look at is the check valves and the tubes that attach to the exhaust manifolds. These can go bad with time and also carbon up. I had to replace both check valves on our car this spring. The valves should only allow air to flow in one direction -- into the manifolds.