DTC U1152, Loss Of Serial Communications - HVAC Programmer: Testing

If multiple class 2 DTCs exist (i.e., DTC U1300, U1301, U1160, U1152), check for intermittent short to voltage or ground in circuit No. 1807 (Purple wire) between BCM 24-pin connector C2 and other modules on class 2 serial data line. See appropriate wiring diagram in SYSTEM WIRING DIAGRAMS article.
If DTC is current, attempt to establish communications with HVAC programmer using scan tool. If communication cannot be established, locate and repair problem in HVAC programmer system. See A/C-HEATER SYSTEM article in the HEATING & AIR CONDITIONING section. If communication can be established, replace BCM. See REMOVAL & INSTALLATION. Recheck system operation.
If DTC is history, check for intermittent open in circuit No. 1807 (Purple wire) between BCM 24-pin connector C2 and other modules on class 2 serial data line. See appropriate wiring diagram in SYSTEM WIRING DIAGRAMS article. Repair as necessary. Recheck system operation.