Cadillac cts 03 wont shift out of park
03 cts module. Ecm was replaced and the car wouldn’t shift out of park. So I replaced the ecm that was under warranty. But I’m getting the same problems with new ecm. Abs/brake/traction lights all onThis is the code I getP0856 How can I find out if it’s a wiring harness open or a faulty ebcm?