xsrfsno225x

It is not a bad idea. All you're doing is uncharging a circuit board. And after about 35 miles, the readiness codes will be fine for any OBDII or vagcom diagnostic.

4Driver4

Not true. You a de-powering *all* the control units in the car. Not just one. Setting may be lost, and better have the radio code handy.

Do it right. Use the tool.

AudiMick

What you are doing is resetting all setup parameters for the car to default. All the learned info is discarded, and if the initial fault was not corrected (oxygen sensor for example) this could cause the car to run even worse than before.

When they spec'd OBDII they considered that sellers or owners would try to use the battery disconnect trick or remove the CEL bulb to clear a CEL, or to pass emissions.

It doesn't work. And if your car won't even move it's a real problem.

xsrfsno225x

not true. i did this. and passed very strict CA emissions aka "smog" test.

whatever this is a dead thread.

Iguana6699

I tried to reset my check engine light with my OBDII today and it didn't clear anything (with ig on and engine off). Manufacture date is 06/98. Using MaxiScabn tool, check engine light did not reset. Guess I need a VW/Audi one. (The light came on due to low coolant level after alternator/battery replacement - I think). The OBD worked on every other car I have had except this one. Also threw 4 codes - 0160, 0501, 1545 and 1600.

Ptreaster

so what you are saying is that you can never change the battery because it will screw up the computer??