Unplug the primary wiring connectors from the AAM. Inspect the harness pins for green corrosion or physical distortion. Use a digital multimeter set to Ohms to test the continuity between the engine speed signal wire pin and the vehicle chassis. If resistance is near 0 Ohms, the wire is shorted to the ground somewhere along the harness runner. 4. Clear the Code and Retest
Some auto upholstery shops can install a universal OCS mat for roughly $400.