Not to be redundant - The manual is very explanatory about what the single or double wrench symbol means as folks have said - "A" or "B" - and resetting this is actually easy - just some timing regarding turning on the ignition and pressing the correct buttons - totally explained in the manual - when I bought my car new, they had replaced the battery and this light came on with like a -5400 (the car only had 13 miles on it) so I read the manual and even I was able to do it the first time...