Does it wait for the car to be in motion for the self test? In the winter I will warm the car up for 10 minutes or so and once I start to back out and get maybe 10-20 feet, it happens. In the summer I only wait 10-20 second for the oil to get pumping and then leave and it happens at just about the same point in backing up. I did some googling and only found one reference to the self test but it sounded like that happens when you first start the car and if the abs and brake lights go off, the test was successful.
