check engine light and CA smog

new/used golf 2006

Active member
Joined
Apr 30, 2007
Location
sf, ca
TDI
2006 golf gls
i had a check engine light.

a friend with a scanner read the code: p0128.

looked this up and learned that this is usually the coolant temperature sensor.

i changed the CTS.

had my friend with the scanner reset the thing.

went to get smogged. it passed emissions, but the thing said that the car's computer wasn't allowing it pass.

i'm assuming that i just need to drive it for a while.

two questions:

1: does that sound right?
2: any idea how long i should drive before getting it retested?
 

TDI-ed

Veteran Member
Joined
Sep 6, 2009
Location
NY
TDI
2 MK4 Golf TDIs; 2004 V10 Toaureg; 2011 Audi A3 TDI
Yes, sometimes when you plug into OBD2 and clear codes, the car needs to run through 1-2 drive cycles for readiness. Always have smog center check OBD2 for readiness before starting smog, that way you don't waste money and time. Search forum for procedure for readiness ... drive it a couple of days, then go in, but have them check readiness before smog.
 

Ed ke6bnl

Veteran Member
Joined
Aug 24, 2015
Location
High Desert So. Ca.
TDI
2002 TDI Jetta
just went to smog my Dodge Ram diesel and during the test a code came up for some transmission relay, didn't pass and I was told to drive it about 100 miles to reset, did that and it test ok and started it up to leave and the trans relay cell went off as I was leaving, O well see him in 2 years.
 

new/used golf 2006

Active member
Joined
Apr 30, 2007
Location
sf, ca
TDI
2006 golf gls
thanks for the replies.

i drove it about 100 miles and went to retest it today. they checked the OBD2 and said the comprehensive component monitor was still not ready.

any advice?

i had a check engine light.

a friend with a scanner read the code: p0128.

looked this up and learned that this is usually the coolant temperature sensor.

i changed the CTS.

had my friend with the scanner reset the thing.

went to get smogged. it passed emissions, but the thing said that the car's computer wasn't allowing it pass.

i'm assuming that i just need to drive it for a while.

two questions:

1: does that sound right?
2: any idea how long i should drive before getting it retested?
 
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