Conditions for Setting the DTC

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The EBCM detects a short to voltage, short to ground or an open/high resistance on the rear wheel speed sensor signal circuit.
The replicated output speed signal is erratic or has electrical noise on the signal causing the 128K pulses/mile engine speed signal to lose pulses.
A defective transmission vehicle speed sensor or output speed sensor can cause inaccurate speed reading, creating faulty replicated output speed signal.