I have heard of the wheel speed sensor, but I would first look into your speedometer problems. Without the input from the speedo, your car will be confused, as it takes the data from the speedo and compares it to the wheel speed sensors.

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-Justin

91 560 SEC AMG - other dogs dd
01 Honda S2000 - dogs dd
07 MB ML320 CDI - dd
16 Lexus IS250 - wifes dd

it's automatic.