U1016 PCM Class 2 Serial Data Line Fault

Diagnostic Trouble Code Chart:

Wiring Schematic:

CIRCUIT DESCRIPTION
The BCM receives a state of health message from the Powertrain Control Module (PCM) through the Class 2 serial data link.

CONDITIONS FOR SETTING THE DTC
The BCM does not receive a state of health message from the PCM after receiving other messages from the PCM.

ACTION TAKEN WHEN THE DTC SETS
^ The BCM stores DTC U1016 in memory.
^ The SERVICE VEHICLE SOON indicator lamp turns on.

CONDITIONS FOR CLEARING THE DTC
^ DTC U1016 changes the status from current to history when the BCM detects a state of health message from the PCM.
^ A history DTC will clear after 100 consecutive ignition cycles if the condition for the fault is no longer present.
^ Using a scan tool.

DIAGNOSTIC AIDS
^ The following conditions may cause an intermittent malfunction to occur:
^ An intermittent open, short to ground, or short to B+ in circuit 1037 or 1049.
^ Poor connections at the BCM or the PCM.
^ The Body Control Module (BCM) may store DTC U1016 if certain diagnostics are performed between the Powertrain Control Module (PCM) and the Data Link Connector (DLC).
^ DTC P1626 will set in the Powertrain Control Module (PCM) when the ignition switch is on with the Body Control Module (BCM) disconnected When BCM diagnostics and repairs are completed, refer to Computers and Control Systems for additional information on PCM related DTCs. Computers and Control Systems

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. This step checks for an open in the Splice Pack SP205.
3. This step checks for a short to ground in circuit 1049.
4. This step checks for a short to B+ in circuit 1049.
5. This step checks for an open in circuit 1049.
6. This step determines whether the malfunction is intermittent or the PCM is faulty.