Communication Error
It is possible to get a test fail error from a diagnostic 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 diagnostic tool whenever the diagnostic tool requests a test. Some are normal responses to valid requests. The others are communication error responses. If the diagnostic tool displays any of the test fail error responses, reinitialize the diagnostic tool. If the error is still present, GO to Pinpoint Test AE , after checking the diagnostic 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.