Can anyone help translate what these codes are trying to say?

[Timco]

[AKnowles]

The Boxster engine includes an emissions device to inject fresh air in to the exhaust (if I remember correctly). There are quite a few threads on it, the codes, and the potential fixes.

Best suggestion I can offer is to clear the codes and see if they return. If they do, then it is time to search for the potential cause. There are many, from failed compressors, failed pressure hoses, etc.

[soucorp]

P0491 Secondary Air Injection System, Bank 1 - Insufficient Flow
P0492 Secondary Air Injection System, Bank 2 - Insufficient Flow

Possible cause of fault
- Electrical fault in power supply or line between relay and secondary air injection pump
- Secondary air injection pump relay mechanically faulty
- Mechanical fault in electrical secondary air valve
- Pneumatic secondary air valve faulty/sluggish
- Electrical fault in secondary air injection pump
- Mechanical fault in secondary air injection pump or secondary air injection pump blocked
- Vacuum system leaking
- Air hose to secondary air injection pump slipped off or constricted


What others have said about resolving this issue:

= This code is a PIA to troubleshoot.... (turned out my cats were bad).

= Went back to my dealer. It was a cracked vacuum tubing -diagnosed and replaced free of charge in 30 mins.

[Timco]

So I found a very comprehensive diagnosis guide online, then today it gave me these same codes again. Time to dig in.

Does the fact that it's both banks and that I am getting an incomplete test result on Catalytic Monitoring, Evaporative system, and Secondary Air system tell me anything? Are these systems related?

Tim

[thstone]

Those codes mean that the ECU is detecting a fault in the secondary air injection system. The SAI is used primarily at start up to reduce emissions when the engine typically runs fairly rich and the cat's may not be up to full operating temp. Use of the SAI leans out the exhaust gas for better emissions.

The basic idea is the ECU commands the secondary air pump to inject extra air into the exhaust gas and then monitors the pre-cat O2 sensors for the voltage to change (to the lean side). If there is no change as the extra air is being injected, then something is wrong with the system and the CEL is illuminated.

The possible failure list is long and their interaction can be somewhat complicated (because its a feedback loop it can be hard to determine where to start - kind of a chicken and egg problem - is the O2 sensor broke and sending out a constant voltage or is the air pump broke and not injecting any air resulting in a constant voltage at the O2 sensor! Or are both the O2 sensors and the air pump working fine but there is a leak or other problem somewhere in the plumbing? Ahhhh!!). This is why Soucorp's list of components to check is so extensive.

Hope this somewhat simplified explanation helps.

[Paul]

After making sure the pump runs, check for vacuum and pressure leaks in the many hoses next.

[Jamesp]

Timco,

Did you fix this? My Box just threw both codes. Woo Hoo! More stuff to learn!

[Timco]

Originally Posted by Jamesp

Timco,

Did you fix this? My Box just threw both codes. Woo Hoo! More stuff to learn!

Yes. It was the check valve that plugs into the intake manifold (I call it Barry) that had broken and the sec air was just pumping into the engine compartment and not into Barry. New generic check valve for $3.

[lkchris]

Originally Posted by thstone

The SAI is used primarily at start up to reduce emissions when the engine typically runs fairly rich and the cat's may not be up to full operating temp. Use of the SAI leans out the exhaust gas for better emissions.

Your wording makes it sound like the extra air "dilutes" the exhaust gas mixture, but in fact the extra oxygen causes the unburned fuel to actually burn. It's not "leaning out," that is.

[woodsman]

Originally Posted by Jamesp

Timco,

Did you fix this? My Box just threw both codes. Woo Hoo! More stuff to learn!

Is this what 'life long learning' is?

[Jamesp]

Timco,

Can you give me Barry's precise address so I can hunt that mother down for a bit of one on one? :troll:

[Timco]

Originally Posted by Jamesp

Timco,

Can you give me Barry's precise address so I can hunt that mother down for a bit of one on one? :troll:

Barry Manifold is right on top. The SAI tube plugs into a black & white check valve then into Barry.

[Jamesp]

Originally Posted by Timco

Barry Manifold is right on top. The SAI tube plugs into a black & white check valve then into Barry.

Thanks Timco. I wus confusulated and didn't connect Barely Manenough. The B&W check valve seems to check, so I'm still in learning mode.

[914nut]

please explain fault code PO1119 on 2000 boxter

[mikefocke]

P1119 Heating of oxygen sensor ahead of TWC, bank 2 (left side looking from the rear, sensor nearest the engine) Could be bad sensor or bad connection or wiring.

More at https://sites.google.com/site/mikefocke2/oxygensensors