U1016 Loss of Communications With PCM - ABS

CIRCUIT DESCRIPTION:
The Class 2 serial data line allows all the modules on the line to transmit information to each other as needed. Each module is assigned an ID and all the information sent out on the line is assigned a priority by which it is received. When the ignition switch is turned to the RUN position each module begins to send and receive information. Each module on the Class 2 serial data line knows what information it needs to send out and what information it should be receiving. What the modules do not know is which module is supposed to send them the information. This information is only learned after the module has received the information it needs along with the ID of the module that sent the information. This information is then remembered until the ignition switch is turned off. If the Electronic Brake and Traction Control Module (EBTCM) looses communication with the Powertrain Control Module (PCM) then DTC U1016 will be set by the EBTCM.

CONDITIONS FOR SETTING THE DTC:
The Diagnostic Trouble Code (DTC) can be set any time the ignition is in the RUN position, and the PCM does not communicate with the EBTCM for 5 seconds.

ACTION TAKEN WHEN THE DTC SETS:
A malfunction DTC is stored, Traction Control System (TCS) is disabled and the TRACTION OFF indicator is turned on. ABS remains functional.

CONDITIONS FOR CLEARING THE DTC:
^ Condition for DTC is no longer present and scan tool clear DTC function is used.
^ Fifty ignition cycles have passed with no DTC(s) detected.

DIAGNOSTIC AIDS:
^ It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
^ An intermittent malfunction is most likely caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation.
^ If an intermittent malfunction exists refer to "Troubleshooting Procedures" in Diagrams.