Driving a Corsa D 2012. Was serviced in August this year, have done 3,000 kms since then. Spanner light flashing up recently, it stays on for about ten minutes and then stays off. No loss of power with the car. Drove over 400kms at weekend, didn't show up once. Just flashed up again this morning on school run. Did the brake pedal/accelerator test - no error codes showing. ??