Communication Error
It is possible to get a test fail error from a scan tool when initiating a test or viewing PIDs. The communication error could be caused by operator error, the vehicle wiring or connectors, or the powertrain control module (PCM) and other control modules connected to the DLC wiring. The PCM responds to a scan tool whenever the scan tool requests a test. Some are normal responses to valid requests. The others are communication error responses. If the scan tool displays any of the test fail error responses, reinitialize the scan tool. If the error is still present, GO to Pinpoint Test AE , after checking the scan tool connections, cable/adapters, and entry of vehicle information. Verify the power take-off system or auxiliary idle control (if equipped) is off when trying to carry out the self-tests.