C1234 is ABS Right Front wheel sensor signal missing.
C1145 is ABS Right Front wheel sensor signal input failure.
C1236 is ABS Left Rear wheel sensor signal missing.
C1175 is ABS Left Rear wheel sensor signal input failure.
Usually these codes mean that either the sensors are bad, the wires to them are bad or the connections are bad.
Additionally with this car it is also possible that the bearings were installed backwards. One side of the bearing has a magnetic ring that the speed sensor reads. If the bearing is installed with that ring to the outside the ABS sensor cannot read it and you get the same two codes.
Usually the two sides are easy to tell apart. The magnetic side is usually black and rotates with the outer race. The "outside" usually has a metal shield.
And just to make it more fun, both bearings are available without the ABS encoder ring on them.
Thursday, February 23rd, 2017 AT 1:33 PM