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Home >> Chevrolet >> 2000 >> Tahoe 5.7 R, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 11 (Body Control Modules) >> Diagnostic Tests >> DTC B1480: Battery Rundown Protection Circuit Malfunction >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 1999 GMC Sierra and 1999 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. If BCM diagnostic system check has been performed, go to next step. If BCM diagnostic system check has not been performed, perform BCM diagnostic system check. See BCM DIAGNOSTIC SYSTEM CHECK  under SYSTEM TESTS.
  2. Turn dome light switch on (defeat switch off). Using test light connected to ground, probe both sides of CTSY fuse (15-amp) located in Underhood Bussed Electrical Center (UBEC). See COMPONENT LOCATIONS  . If test light illuminates on both sides of CTSY fuse, go to step  6 . If test light does not illuminate on both sides of CTSY fuse, go to next step.
  3. If test light illuminates on either side of CTSY fuse, go to next step. If test light does not illuminate on either side of CTSY fuse, go to step  5 .
  4. Repair short to ground in Orange wire between UBEC connector C1 terminal A1 and center high mount stoplight/cargo light terminal "A". See WIRING DIAGRAMS  . After repairs, go to step  16 .
  5. Replace UBEC. After repairs, go to step  16 .
  6. Turn ignition on. Using scan tool, monitor current DTCs. Connect fused jumper between ground and Brown BCM connector C1 terminal A8 (Dark Blue wire). See Figure . If scan tool displays DTC B1480 as current, go to next step. If scan tool does not display DTC B1480 as current, go to step  15 .
  7. Disconnect Blue BCM connector C2 and remove connector combs. Ensure fused jumper is still connected between ground and Brown BCM connector C1 terminal A8 (Dark Blue wire). Using DVOM, measure voltage between Blue BCM connector C2 terminal B12 and ground. See Fig 1 . If battery voltage exists, go to step  15 . If battery voltage does not exist, go to next step.
  8. Remove jumper from between ground and BCM connector. Remove inadvertent power relay from Mid Bussed Electrical Center (MBEC). See COMPONENT LOCATIONS  . Using Connector Test Adapter Kit (J 35616-A), connect DVOM between ground and inadvertent power relay connector terminals No. 1 and 5 (top 2 terminals of relay connector). If battery voltage exists on both terminals, go to next step. If battery voltage does not exist on both terminals, go to step  13 .
  9. Disconnect Brown BCM connector C1 and remove connector combs. Using Connector Test Adapter Kit (J 35616-A), connect DVOM to measure resistance between Brown BCM connector C1 terminal A8 and inadvertent power relay connector terminal No. 2 (lower left cavity of connector). See WIRING DIAGRAMS  . If resistance is 0-5 ohms, go to next step. If resistance is not 0-5 ohms, go to step  11 .
  10. Using Connector Test Adapter Kit (J 35616-A), connect DVOM to measure resistance between Blue BCM connector C2 terminal B12 and MBEC connector C1 terminal A10. If resistance is 0-5 ohms, go to step  14 . If resistance is not 0-5 ohms, go to step  12 .
  11. Repair open in Dark Blue wire between Brown BCM connector C1 terminal A8 and inadvertent power relay connector terminal No. 2 (lower left cavity of connector). See WIRING DIAGRAMS  . After repair, go to step  16 .
  12. Repair open in Orange wire between Blue BCM connector C2 terminal B12 and Mid Bussed Electrical Center (MBEC) connector C1 terminal A10. See WIRING DIAGRAMS  . After repair, go to step  16 .
  13. Repair open in Orange wire between UBEC connector C1 terminal A1 and MBEC connector C2 terminal C2. See WIRING DIAGRAMS  . After repair, go to step  16 .
  14. Replace inadvertent power relay. After replacing relay, go to step  16 .
  15. Replace BCM and program. See BODY CONTROL MODULE (BCM)  under REMOVAL & INSTALLATION.
  16. Reconnect all components. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES (DTCS)  under SELF-DIAGNOSTIC SYSTEM.
Fig 1: Identifying BCM Connector C2 Terminals
G99F02308Courtesy of GENERAL MOTORS CORP.
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