2002 EV: Issue with SAI (Secondary Air Intake) System

[rstrube]

Hi all,

We took the van out camping this weekend and unfortunately encountered some very rough dirt roads. The next day when driving home I noticed the check engine light was on. We plugged in our code reader into the OBD-II port and the code that read out was:

P0411 "Secondary Air Injection Incorrect Upstream Flow Detected".

My understanding after doing some research is that this could be a problem with:

1. SAI Pump itself
2. Combi Valve
3. Vacuum Solenoid
4. Vacuum hoses themselves (between solenoid and combi valve, and between solenoid and intake manifold vacuum)
5. Air hose between SAI pump and combi Valve

Questions:

#1 SAI Pump
For the SAI Pump I'd love to rule out the fuse. I feel really stupid because I can't seem to find the fuse for it anywhere. I tried under the driver's seat, the driver's side knee bar, and the little fuse box in front of the battery. I also haven't been able to locate the main relay panel (other than the relays near the drive's knee bar). Any advice on this would be welcome!

I've also read that the rivets on the SAI Pump can come loose over time and that you can replace them and tighten everything down. Has anyone ever done this? Finally is there a way I can test the pump independently? Can I just apply 12v to it to see if it runs?

#2 Combi Valve
I've read that you can apply a manual vacuum to the combi valve using a special tool to determine if it opens or not. Not sure if this is a common point of failure.

#3 Vacuum Solenoid
Is this a common point of failure? I read that you should be able to hear it click if you apply 12v to it.

#4 Vacuum Hoses
Apparently these can crack. The seem like they have a surprisingly small diameter. Can you replace them will off the shelf vacuum hoses or do they need to be a particular shape, etc.

#5 Air Hoses
These are the thick black plastic hoses, do these crack often? These look like there are a very specific shape. If these are cracked, what would you recommend I replace them with?

Thanks for any advice you can provide!
Rob

[EuroTec]

The plastic hoses are notorious for cracking. Check those first, especially after the rough roads.
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If it ain't broke, don't fix it!

[gesoffen]

[rstrube]

Hi all,

I really appreciate the responses.

The only thing I'm a bit confused is what relay / fuse is responsible for the SAI pump. I think I saw relay 53? Does that ring a bell?

Rob

[gesoffen]

That relay number (e.g. 53) is really identifying a type of relay, not necessarily a position/location. There are several "53" relays in the late model eurovans. I don't recall if the SAI uses a 53 relay, though that sounds right to me based on how 53 relay's work as it uses a low current signal to turn on/off a high current device.

Before you dive into the electrical side of things, especially relay troubleshooting, I'd strongly suggest you check the air tubing/vacuum lines first and pump second. If I recall from one of your posts, you were recently doing something with the SAI system or EGR system? If so, those areas that your hands were recently on would be on my prime suspect list.
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1973 VW Superbeetle (1302) w/ RAT 2270 T4
2003 VW Eurovan Weekender w/ 2.8L VR6 AXK, DYA 5 Spd Manual Conversion

[rstrube]

Thank you! I'll checkout out the usual suspects first!

[EuroTec]