Check Engine Light

So I've had an MIL on the wagon since I bought it and I think it's time to start trying to fix it. The codes I'm getting is a P0441(Evaporative Emission Control System Incorrect Purge Flow) and P0411(Secondary Air Injection System Incorrect Flow Detected), according to the little bit of research I've found I'm thinking of starting on on the rear O2 sensors. Any guidance with this would be much appreciated.

The codes indicate that the purge valve and the AIR valve or associated parts are not functioning properly. Nowhere in the codes you stated is there the remotest hint of a reference to the O2 sensors, so why would you start with them.

Because it just passed emissions with FLYING colors, that to me tells me that the functional part of emissions is working.

Check the canister, and trace the lines to make sure nothing is disconnected (or broken).  Let me pull my manual as well.  Will edit once I get my books out.

Edit (sort of long winded, sorry!)

Potential causes of a P0411:
Damaged or missing check valve
AIR pump intake port plugged/damaged
AIR pump clutch malfunction Holes
damage to exhaust components


With these, I would check the vacuum lines first, especially with the vehicle age, and the potential for dry/cracked lines. There could be a valve issue as well, as Fred stated.

There are two types of pumps on the cars - mechanical and electric.
With the longer diagnosing of the pumps, I won't get into these, but you can research (I picked up a Haynes manual for mine, and they list a lot). They also list the air control valve and a few other possibilities for you to check.


A code P0441 possible causes:
Bad vacuum switch
Broken or damaged EVAP line or canister
Open in PCM purge command circuit
Open or short in Voltage feed circuit to Purge Solenoid
Faulty purge solenoid
Restriction in EVAP solenoid, line or canister
Corrosion or resistance in purge connector Bad PCM

This is where I first suggested to check the canister and lines.

To expand, with the canister, there are 3 possible types...yay (not!).
1) Ported vacuum source - a ported vacuum source from the throttle body directly to the EVAP control valve.
2) Manifold vacuum with EVAP purge control valve - this type uses a manifold signal to a separate purge control valve that is mounted on the engine, or on the canister.
3) EVAP purge control solenoid - uses a computer control solenoid to regulate the vacuum signal to the EGR using a pulse modulated signal.

Before replacing anything be sure to check ALL lines in and out of the canister for kinks, leaks, or breaks along the entire length of the line. (Yes, that is the 3rd time I said that lol, sorry). Check the gas cap gasket (that big rubber o-ring thingy!) for cracks, breaks or signs of drying out (this is a possible cause of the code as well (according to Haynes!).

On vacuum systems, check pressure in lines and check the vacuum pump for breaks or leaks.
On Purge control valve systems, check for power going to the solenoid. Beyond that is most likely replacing that part (or worst case, having a PCM issue.)


(Wowzers that was a lot)
(I picked up the "possible cause" list from obd-codes.com, and coorelated with my Haynes manual, and personal experience with the EVAP code with cars I see at work, and talking with mechanics about the issue - yay PA inspection laws teaching me things (ugh))

Hope this helps and doesn't melt your brain.

The P0411 might be related to an air pump disable. I'm not certain what code that will set in a 96. The disable procedure was mandated by GM, but requires a reprogramming of the PCM to prevent the code from setting after the pump is disabled. The rear oxygen sensors might be implicated in other cars, because the system monitors them for a lean condition to verify the pump is working, but would not be at all relevant in a 95 or 96 B-body that has had the pump disabled.

The only thing the rear O2 sensors are there for are to test the catalytic converter.

The system is relatively smart with one major exception. If you get an "O2 sensor lean" reading or similar, it usually means an air leak upstream somewhere, which eventually skews the system far enough to trip that code.

Start with the gas cap. Simple and cheap to replace. That's the most common issue for Evap testing, people don't tighten them enough. By now the seals are drying out.

FWIW I helped design and implement the first year OBD2 system at Chrysler. I'd recommend not buying a '96 Chrysler... we were a little short staffed.

Make sure the relay is actually plugged in for the air pump,.

FWIW, the AIR pump check valves are the reason the AIR pump fails. They are dirt cheap, like $8 apiece from Rock Auto.