How to fix VW code P0491 Secondary Air Injection Low Flow

And this video will be diagnosing a p0491 secondary air injection low-flow on this Volkswagen Passat with a 2.5 L engine.
First we verified the air injection pump was working and it was then we checked the pressure sensor and moved on to test the combination valve for the air injection by applying power and ground to it. On this particular vehicle the air injection combination valve ended up being bad.
2013 Jetta 2.5
2012 Passat 2.5
Customer Concern: Trouble code P0491 Secondary Air Injection System: Bank 1 Insufficient Flow stored. System seems to operate normally.
Average Reported Mileage: 23000
Tests/Procedures: 1. This system uses a pressure sensor to monitor secondary Air Flow from the AIR Pump. At the secondary air sensor there is a 4 pin connector that will have 3 wires. The Brown wire is sensor ground at pin 1. Pin 3 is the 5 volt reference and pin 4 is the sensor signal to the ECM.
2. Backprobing pin 4 key on with the air pump off the signal voltage is approximately 2.60 volts. Activating the pump with the combination valve closed should see the voltage rise to about 3.60 volts.
3. When the combination valve is opened, the voltage should fall to about 3.25 volts if the system is flowing properly.
Diagnostic Codes
DTC 16875
P0491
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[@weldingslife5382]

So are you gonna show how to fix it?!??

[@shanedude120]

does the polo 1.6 tdi cr have secondary air injection ? please reply

[@robertm.1542]

Hi I have the same code on my 2013 Jetta gli what would the cost be roughly

[@pedroinacio5084]

I got quoted for a 1k so that’s why I’m here lol

[@Mn09lfV6f]

Where are the parts located on the V6?

[@abbsgarage.9676]

Under the manifold.

[@andrewcalles5703]

I did my clutch and i did break my o ring and got another o ring and still have the same code but i had to be something simple because before i did my clutch it was working

[@berenicedrabo1573]

Useless video

[@chrisfincher5465]

Once the faulty component is replaced, will the check engine light turn off on its own?

[@angulo3047]

Hey bro did you get that figured out??

[@angulo3047]

I have the same issue with the check engine

[@diddy60]

Did anyone figure it out? I have a 2018 vw Passat se do I guys think it might be under warranty?

[@tlalok08]

So i have the same issue had it for over a year, took it to a shop and they "replaced" the combination valve and the sensor. Problem still exist. I have a friend mechanic so hes going to look into it will report after!

[@Sheepdog34]

how did it go? @@tlalok08

[@MrMaxwell1589]

The title of the video says how to fix it

[@williehaidari7673]

Hi, I have a 2012 Vw New Beetle 2.5L Check engine light came on with code p0491 and it failed C.A. smog test. My mechanic wants me to change Combi valve and secondary air pump. I don't believe him, I'm not sure if he's trying to scam me? Any feedbacks are kindly appreciated. Thanks

[@tctk1]

Lol this could be 100 different things with the SAI, trust me I helped design it on the 3.0 Audi tfsi

[@JARMotors]

no you didn’t

[@KingZoneOne]

So this is YOUR fault then (Pun intended)? 😜😂

[@scuba422123]

rust causing it to stick I think.. and not a fan of vw

[@FlatRateMechanic]

Yup would have to agree.

[@neondiamondsaquaberry17]

You’re not alone !

[@doginu]

You should stick with your KIA

[@jasonmeyers9413]

Kia sucks timing belt issues

[@AltruisticWarrior]

My VW has 210k and up to that point it's only cost me 1100 in relatively minor repairs... most of them in the last 10k but they're to be expected for the years and miles. Oil cooler, rear door lock(from years of pizza delivery), serp belt, alternator, pulley tensioner and a few sets of breaks... that's it. To be fair its probably their best but slowest engine, 2.0 CBPA paired with a manual. 😅 I was just here looking up this code for a friend's Passat. I tell everyone I know, get a basic 4 cylinder paired with a manual and that alone will generally get you a reliable car.

[@tomlinkinsrealtor5247]

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