DTC U1064: Loss Of BCM Source Id 40: Description

BCM sends a state of health message to each module connected to class 2 serial data line. DTC U1064 will set when BCM does not receive its own transmitted messages. No driver warning message will be displayed. If conditions for malfunction no longer exist, history DTC will clear after 100 consecutive ignition cycles. DTC U1064 will also clear when scan tool is used to clear codes.

NOTE: When ignition switch is turned to RUN position with BCM disconnected, PCM-related DTC P1626 will be set. After BCM repair is completed, see appropriate TESTS W/CODES article in ENGINE PERFORMANCE section:

TESTS W/CODES - Century
TESTS W/CODES - Regal