P0410 Secondary Air Injection / cleaning M104 head passages

[97 SL320]

Can head AIR passages on a M104 be cleaned without removing the head?

Got this error code today on the 97 C280 M104 inline 6 , 161 K miles

P0410 Secondary Air Injection System Malfunction
Doing a search, the computer is looking for a drop in O2 sensor voltage within 60 sec of the air pump turning on. The pump runs about the same times as my 97 SL320 M104

I still need to check the inlet screen on the pump, test solenoid / diverter valve / vac hoses.

[ILUVMILS]

Make sure you don't have a lazy o2 sensor before you before you do anything else.

[oldsinner111]

My code came from,not using vacuum on the egr looking thing on the exhaust manifold.I simply ignore it.It has not hurt my 1/4 mile times.

[97 SL320]

Originally Posted by ILUVMILS

Make sure you don't have a lazy o2 sensor before you before you do anything else.

Yes, I was considering that due to mileage, . . and, got a P0136 ( rear O2 sensor ) on the way to work today.

From research it seems the computer looks at front sensor to determine AIR pump operation. In any event they are both due for a change.

[97 SL320]

Small update.

Changed front and rear sensors. ( you can use a rear sensor for the front, the only difference is the wire length )

So far the rear O2 sensor code has not come back.

The AIR readyness test has not completed, getting a P0410 in the pending code list after clearing all codes.

Put a vacuum pump on the diverter valve control, the diaphragm holds vac. Put a vac gauge inline, ran engine and getting vac when the AIR pump is running. Next step is to clean screen on AIR pump, remove outlet hose and feel for flow, pump air into diverter valve while using vac to hold the valve open and judge restriction.

[97 SL320]

Another update.

Pulled AIR valve at head, ran pump lots of air, blew compressed air into the head, didn't get any restriction. Pulled ignition coil cover to inspect vac hose that runs from solenoid to air valve. Found plastic vac crushed / broken that leads to air valve. Repaired line.

In the post above, I had tested for vac at the solenoid because I had replaced a bit of rubber hose. The test showed OK because the line was crushed on the solenoid side.

Cleared codes, jumpered the pump , pulled vac on the air valve, watched front O2 go from 0.600 ish to 0.005 very rapidly. Will drive and wait for diag monitors to run.