2005 Jetta TDI wagon OBDII "not ready"

My 2005 Jetta TDI wagon failed smog due to the OBDII coming up "not ready". It passed in every other category. I drove it for 100 miles, rechecked and refailed the smog. Do I have to do the 8-step (dangerous!) drive cycle to fix this problem? Is there another way to fix this annoying computer glitch? Thx.

It's always possible there is an actual problem . . . . in any case, this is in no way a 'glitch' - it's a designed in set of tests, and working as designed. If all is good, the bigger question is what unset it? Did the car perhaps lose power at some point? Oh, and it takes s number of drive *cycles* to clear . . . one excursion, no matter how long won't do it . . .

Does it say what isn't ready? It should say which system didn't set.

The guy's scanner at the smog check place said "INC", meaning the computer was "not ready". He was the one that told me to drive it 50-100 miles and come back. I read online somewhere that some OBDII scanners are non-VW compatible, so I bought a cheap VW-compatible U281 scanner. It gave me a code that wasn't in the book it came with! The plot thickens. Will get it properly diagnosed by a mechanic hopefully this week. Thanks for your replies.

There are multiple monitors, and tne OBD spec allows seeing of the status of each individually . . . so I suspect that thr smog check station chooses to nlt confuse thier staff with useful info, but rather just 'go/no go' since any not ready is a fail most places. The good news is that any actual OBD-II scantool should read the specifics . . . In the use, if VWdidn't speak basic OBD, it would be illegal . . . the point of OBD is that *everything* in the US speak it. About the only issue I could think of would be anolder scanner that can't speak CAN protocol. Oh, and since OBD codes are unrelated to the tool used, you should be able to lok up your code online. More significantly, check readiness monitors . . . not the same as scanning codes!

Does your car have a tune with EGR delete? A number of old tunes would fail to set the EGR readiness monitor with their deletes, even though no codes are stored...

b99forever said:

My 2005 Jetta TDI wagon failed smog due to the OBDII coming up "not ready". It passed in every other category. I drove it for 100 miles, rechecked and refailed the smog. Do I have to do the 8-step (dangerous!) drive cycle to fix this problem? Is there another way to fix this annoying computer glitch? Thx.

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Find someone with a VCDS, so then you can find out what exactly is not ready.

Got a mechanic to take it home overnight and drive it well over 100 miles and get the engine nice and warm and was able to "reset" and I was able to get it to pass smog. A month later the MIL came on. Took it in and was told the sensor for engine coolant temperature was failing, so they replaced ECTS. Two weeks later (yesterday) the MIL came on again. (The engine thermostat was replaced over the summer.) Any ideas? I guess I have to go in again to figure out what the error code is. SO frustrating.

Without seeing a scan directly from the vehicle, it is all wild guessing game of "open wallet and toss parts". or maybe with a touch of

b99forever said:

Got a mechanic to take it home overnight and drive it well over 100 miles and get the engine nice and warm and was able to "reset" and I was able to get it to pass smog. A month later the MIL came on. Took it in and was told the sensor for engine coolant temperature was failing, so they replaced ECTS. Two weeks later (yesterday) the MIL came on again. (The engine thermostat was replaced over the summer.) Any ideas? I guess I have to go in again to figure out what the error code is. SO frustrating.

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One thing that can be a common problem on these cars that you can check without a scan is your grounds. There is a major chassis ground hidden underneath the air cleaner box that does work loose and will cause a bunch of issues.

A common misconception about a scan is that it will magically tell you what parts to replace. A scan is only a part of the diagnosis process. Step one should always be to look for obvious problem before you even consider doing a scan. Loose ground or disconnected vacuum hose or something else super simple and obvious, maybe?

Ol'Rattler said:

...........................A common misconception about a scan is that it will magically tell you what parts to replace. A scan is only a part of the diagnosis process. Step one should always be to look for obvious problem before you even consider doing a scan. Loose ground or disconnected vacuum hose or something else super simple and obvious, maybe?

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Seems this needs posted once a day.