# Cold start no RPM rise



## avmech (Aug 19, 2006)

During a cold start with my 2012 Passat 2.5 SE CBUA I rarely get the rise in RPM above idle. I currently have the old P0106 but nothing else pops. Occasionally, It goes up to the normal cold start range and slowly comes back to standard idle, but more often than not, it doesn't. I have replaced the Baro sensor, the valve cover, the air filter and mopped out the intake and PCV tube. I have no driveability problems, so at this point I am basically ignoring the CEL for now. Any ideas?:banghead:


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## avmech (Aug 19, 2006)

*Still looking for some wisdom...*

No ideas on this? I am still experiencing this situation with no RPM rise on a cold start, but oddly enough, sometimes its works as advertised. I still have the P0106 which I have basically given up on after a sensor, air filter, valve cover replacement and intake, PCV and TB clean. I am not going to continue to throw money at it as long as I have no driveability issues.


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## halbwissen (Jul 20, 2001)

My guess is the SAI isn't running because temperature is too low which is related to the cold start rpm. 
Whatever the case, both my previous BGP (SAI) and current CBTA (no SAI) do not idle high in cold temperatures either.
Seems to be normal to me.


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## avmech (Aug 19, 2006)

Thanks. I have owned this car for several years and guess I never noticed no RPM rise during cold weather cold starts. I might just be focused on it because of the P0106 CEL. Appreciate the reply.


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## afawal2014 (Jul 13, 2016)

I'm not sure about the CBUA engine, but on my CBTA engine there was a software upgrade for this issue. Maybe check with your local dealer.


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## Ronny Bensys (Apr 17, 2014)

Check coolant temp. sensor and outside air temp. sensor too. These are the two other sensors the ECU takes into account when it decides to cold start or not.


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## Newparts.com (Jul 12, 2017)

Have you tried to clean the throttle body and do a basic setting?


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## avmech (Aug 19, 2006)

Newparts.com said:


> Have you tried to clean the throttle body and do a basic setting?


I have certainly done this chasing after my P0106. I am betting on my not noticing this before, but think I will have a look at the CTS and OTS. I have read here that the CTS may play some part in my P0106 as well, so maybe I'll just replace it and see how it goes. Appreciate the info!


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## avmech (Aug 19, 2006)

afawal2014 said:


> I'm not sure about the CBUA engine, but on my CBTA engine there was a software upgrade for this issue. Maybe check with your local dealer.


I hate taking the car to the dealer, but I need the brake fluid and coolant flushed anyway, so I will ask that they flash the latest engine control software while I'm there. I guess I'll have to reset the P0106 code so I don't have to fight with them about fixing it though....


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## le0n (Jun 12, 2013)

don't reset the codes.

they won't know how to fix it anyway, hah hah. see the P0106 threads in this 2.5l subforum.

is there really an issue if the rpms stay low?

with my manual rabbit, the rpms drop to idle the moment i shift into gear, regardless if it has only been 1 second vs 5-10 seconds.

seems less likely to bang into gear if you drive an auto.


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