P2440 and P0411, Secondary Air Injection

[wormwood1978]

2008 Trailblazer, 4.2, 109,000

Last three cold start ups there has been a roar from the engine compartment for a short time before it goes away; my initial thought was fan clutch and its something I can fix as I replaced my water pump this summer. However, when listening to the sound with my hood up, it sounded closer to the throttle bottle or firewall rather than from the fan clutch. (youtube video)

This has happened the last three cold starts and lasts 5-10 seconds. Has not occurred during warm starts.

Trouble codes are P2440 (secondary air injection system shut-off valve stuck open). P0411 (secondary air injection system shutoff valve stuck open).

I checked fuses 54, 55 and 56 all related to the secondary air system and all fuses were not blown. I looked at the live data on my non bi-directional scanner and nothing looked off (youtube video)

Is the likely fix to replace the secondary air injection check valve (Rockauto $125)? Something else? Is there troubleshooting I should/can do? Is the vehicle okay for short trips, longer trips until I get the parts? <<<<edited to add a comment from Roadie years ago about the SAIS: If you can get one cheaper on-line, no need to rush to install one unless you're in a hurry to pass an emissions test. The SAIS function is only to hasten the engine's entry into closed loop mode on a cold start-up. It's an EPA mandate that reduces emissions, but it has guaranteed zero effect on driving once it's warmed up a couple of minutes.>>>

I checked fuses 54, 55 and 56 all related to the secondary air system and all fuses were not blown. Hoses all appear to be good, wire connectors all appear good. I looked everywhere but especially focused on the secondary air injection valve.

 

[christo829]

Some of us have gotten a block off plate for the port on the engine, removed the SAIS valve and pump, then had the SAIS related codes deleted. If your valve was stuck open, it can allow water to accumulate at the pump, which will eventually kill the pump.

The valve can easily be stuck open and not blow fuses. It's still attempting to function electrically, just not sealing properly, so it doesn't overload any fuses, but fails when the PCM checks, so it throws a code.

Otherwise, yes, replacing the solenoid on the engine should solve the problem as long as it hasn't allowed moisture to compromise the pump assembly.

Good Luck!

Chris

 

[wormwood1978]

Some of us have gotten a block off plate for the port on the engine, removed the SAIS valve and pump, then had the SAIS related codes deleted. If your valve was stuck open, it can allow water to accumulate at the pump, which will eventually kill the pump.

The valve can easily be stuck open and not blow fuses. It's still attempting to function electrically, just not sealing properly, so it doesn't overload any fuses, but fails when the PCM checks, so it throws a code.

Otherwise, yes, replacing the solenoid on the engine should solve the problem as long as it hasn't allowed moisture to compromise the pump assembly.

Good Luck!

Chris

I did some thread research before I posed my question and saw where there was discussion about the blocking plate. It was a little confusing to me though where there were mentions of tones or toning, it seemed a little more complicated that just deleting codes.....deleting codes as in erasing the trouble codes with my scanner or is it making changes to the ECM?

I ordered the gasket and OEM check valve from Rockauto and it should be here tomorrow, $139. Quite possible moisture in the pump and changing that might be my next step if need be or in the future.

I started doing much of own car troubleshooting and repair with this Trailblazer 7 years. This TB has not be a troublefree vehicle by any means!

 

[Mooseman]

None are. They all have their faults. If they built a trouble free vehicle, it would be expensive and they wouldn't make any money on it.

For the money you spent on the parts, you could have removed the whole system and be done with it forever. There is still the blower that can fail and those replacement parts could fail again.

Tuning is a process where you remove the PCM and send it to a tuner to remove the related codes. It's $99 shipping included.

 

[wormwood1978]

I think I can close my problem out as fixed. Turns out one of the two hoses that connects to the secondary air injector pump got disconnected and the quick connect on that hose connector no longer wants to hold. I have rigged it with a cable clamp and may have to add a second clamp based on how the hose connects to the pump. Does anyone know what the actual part number is of the secondary air hose pump connector? I've looked at part diagrams, searched here and at trailvoy, dorman, google and ebay,...nada on just the connector.

 

[xavierny25]

I think I can close my problem out as fixed. Turns out one of the two hoses that connects to the secondary air injector pump got disconnected and the quick connect on that hose connector no longer wants to hold. I have rigged it with a cable clamp and may have to add a second clamp based on how the hose connects to the pump. Does anyone know what the actual part number is of the secondary air hose pump connector? I've looked at part diagrams, searched here and at trailvoy, dorman, google and ebay,...nada on just the connector.

I have the hoses and whole system sitting in my shed if you want them I can get you a price for shipping and it's all yours.

 

[wormwood1978]

Thank you for the o-ffer but I'll pass. I believe I found the part number for the secondary air hose pump connector, Dorman 800-037.

 

[wormwood1978]

Just so anyone who reads this threat at some point in the future looking for the part number, I do not think the Dorman 800-037 is correct. The marking on the part says Norma PA12-GF-20. It is available on Ebay.