Andrew,

12812 is for accelerator pedal position sensor A to B. Check pedal connector for damage or loose wires. Also look at the VSM connector which is located directly under the floor board with two connectors that look the same. They should be marked A or B, maybe 1 or 2. Look at either A or 1 and check all wires for loose connections. 12820 is for a steer sensor. Check both steer wheels for plastic wrap and wires hanging. Sensor should mount into the top of the steer axle just inside the wheel.