[Codidly5]

When did the Jetta start coming with OBD2? I know most Mk3's have OBD2, but some 95's have OBD1... I just want to know how to tell with a Mk3, how to tell whether it has OBD1 or OBD2. Thanks!

 

[Dave926]

:facepalm:

 

[duffmanh06]

:facepalm:

i agree





1996 btw. so mk3, not 2

 

[Codidly5]

Sorry, this must be frustrating to most people. But I'm just trying to learn more about them, I'm trying to get into the vw scene, and want to know as much as possible.

 

[Satur9]

Easiest way to tell OBD1 vs. OBD2 is that OBD1's only have one 02 sensor and OBD2's have 2 of them. There are other things too, i cant remember off hand but the throttle bodies are different too

 

[Mr.V_Dub]

Go to the mk3 forum? lol

 

[steveo27]

wrong forum...

....but, they mid the switch mid year '95.

• ~1994: Motivated by a desire for a state-wide emissions testing program, the CARB issues the OBD-II specification and mandates that it be adopted for all cars sold in California starting in model year 1996 (see CCR Title 13 Section 1968.1 and 40 CFR Part 86 Section 86.094). The DTCs and connector suggested by the SAE are incorporated into this specification.
• 1996: The OBD-II specification is made mandatory for all cars sold in the United States.

 

[justin717]

VR6: OBD-I has metal valve cover, external isv
OBD-II has plastic valve cover, internal isv, and has "AAA" stamped in between first and second runner.

I know there are easy to tell things on an ABA but I cant remember off the top of my head.

 

[steveo27]

ABA - throttle body has a built in IAC on OBD2 as well.

all OBD2 VWs have 2 O2s (pre/post cat), where OBD1 only has a pre-cat O2