xmarine99

We just changed out oil pressure unit and hour later check engine light came on for the first time.Its showing a P0410 code,secondary air injection fault.Is this just coincidence?Has Murphy struck again?What is the fix?

Florida99

Just solved a p0410 code (99 coupe, 70k miles) and want to give a little longer response because you have a good search thread name. While mine was unrelated to oil unit and I doubt yours is, (unless you disconneted the air hose between pump and check valves) someone wrote in another post to check the micro relay in fuse box next to battery and of course the air check valves might need some carb spray (search, there are a lot of other posts on what & how to do). There is also a thread comment that 0410 is always the check valves. Not true.

Was busy and didn't have time to troubleshoot, dealer diagnosis was $105 and response was replace passenger side air check valve for $600 After realizing 0410 is emissions related and not critical for driving or safety, did troubleshoot myself.

I actually did repace driver side check valve (about $15), sprayed pass side and changed air pump (about $60)before finding micro relay suggestion. Take a look inside fuse box next to battery, believe Air Pump is #37 but look at key code on inside cover. There are identical relays in fog lamp and I believe horn. Swap relays to see if that clears 0410. I swapped with fog lamps and found fog lights wouldn't work with bad relay and of course 0410 was fixed. That's what my prob was. If relay, about $15. A whole lot cheaper than $600

Paul Wood

Find a tuner and have the parameters changed so that the system never checks itself and it never throws a code. I did this after a month of frustration replacing parts and spending money. The whole AIR system is a crock and does absolutely nothing for your car.

mcm95403

Thanks for the info! The search function is a great thing!

xmarine99

I swapped the horn relay and it didn't help.Horn worked with airpump relay

mcm95403

Yep, I just tried swapping it with the fog light relay and the fogs still work. I cleared the code so I'll have to wait to see if it comes back.

lucky131969

No info in your sig, what year you have, depends on how you troubleshoot, and how many relays there are.

mcm95403

Updated the sig - now Nassau Blue Metallic 99 Z51 6 speed coupe pilot

Searching around it appears that the pressure diagphram in the pump goes gad and can cause this. I'll check that out Wednesday evening.

Taiman

I change the sec pump and drove around and the code came back.