vwcorvette (Forum Supporter)
vwcorvette (Forum Supporter) UberDork
4/23/22 1:06 p.m.

2012 Smart fortwo pure. P0401 secondary air fault. Replaced the seized air pump. Replaced the combi valve (not staying open with vacuum). All vacuum lines good. Combi valve vacuum switch is working and I have about 19 inches of vacuum. Cleared codes. Drove to set readiness codes. Fault returned.

Of note: The replacement combi valve was purchased used off of eBay. It holds vacuum when I use my hand held pump, but barely 5 inches. Should it open all the way once vacuum is applied and hold it open at 19 inches without having to continuously pump?  

Unfortunately I don't know anyone around here (Vermont) with a smart I could check their combi valve.

vwcorvette (Forum Supporter)
vwcorvette (Forum Supporter) UberDork
4/25/22 8:45 a.m.

Anybody with thoughts?

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) SuperDork
4/25/22 10:11 a.m.
vwcorvette (Forum Supporter) said:

Should it open all the way once vacuum is applied and hold it open at 19 inches without having to continuously pump?  

That is how I have had them work before. Seems like yours may be leaking internally?

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