DTC U1153, Loss Of Serial Communications - CCP: Notes
WARNING: This page is about a different car, the 1997 Cadillac Seville, 1997 Cadillac Eldorado, and 1997 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
To identify wire colors and components on Class 2 serial data line, see appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS.
Every 2 seconds while ignition switch is in RUN position, control modules that communicate on class 2 data bus transmit a performance condition signal to indicate system is operating properly. Signal is then transmitted to PZM. DTC U1153 will set when PZM does not receive signal from Climate Control Panel (CCP) after 3 consecutive monitoring cycles. DTC U1153 will clear when CCP transmits signal to PZM.