How to Fix BMW Air Injection Codes: P0491 and P0492 "For Free"

How to Fix BMW Air Injection Codes: P0491 and P0492 "For Free"

In this video, I will show you how to fix BMW the air injection codes p0491 and P0492.
P0492: Secondary Air Injection System Insufficient Flow Bank 2
P0491: Secondary Air Injection System Insufficient Flow Bank 1

Flat rate mechanic here again and we got this BMW in here for a check engine light and we got a couple codes we got a p0491 and a p0492 BMW secondary air injection so we got some kind of air injection problem as far as the flow goes and I just wanted to go over what we found when we were diagnosing this basically the first thing we did we pulled out the this is the actual air injection pump itself we just disconnected it if I applied power and ground here pumps seem to be working fine so we went ahead and did is um if you look down here the air pump this usually is going to mount right over here like this

We pulled this up so we could get to the diverter valve here um the diverter valve is controlled by vacuum and this vacuum line goes to a vacuum electronic vacuum switch which is located down behind the intake here so we tried activating this with a scan tool we weren’t getting any airflow we did verify we weren’t getting any airflow the air pumps coming on so all that stuff’s good on what we found is we’ve got a there’s actually if you follow this vacuum line down behind the intake you got a check valve here and the vacuum hose was actually actually broken off so the vacuum switching valve wasn’t supplying power or wasn’t oh wasn’t flying back into the diverter valve so let me see if I can actually see back yeah I don’t think you guys are going to be able to see that but the vacuum switching valve is right behind here and it connects to a port in the back of the intake manifold so ultimately what’s going to fix this one is just repairing as simple as repairing you know this rotted out vacuum line so we’ll fix that verify the repair and hopefully this BMW will be good to go thanks for watching if it’s helpful be sure to hit the Thumbs Up And subscribe to the flat rate mechanic

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