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Home >> Cadillac >> 2000 >> Seville SLS >> Repair and Diagnosis >> Body & Frame >> Mirrors >> Power Mirror System >> Diagnostic Tests >> DTC U1170: Loss Of Left Front Door Module Simple Bus Serial Data >> Diagnostic Procedure

Diagnostic Procedure

  1. Perform DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. Go to next step.
  2. If DTCs U1161, U1162 and U1163 are also set as current, go to step  6 . If DTCs U1161, U1162 and U1163 are not set as current, go to next step.
  3. Check for an open in Tan/White wire between Left Front Door Module (LFDM) connector C1 terminal No. 15 and Left Front Power Window Switch (LFPWS). See appropriate wiring diagram in MEMORY SYSTEMS article. Repair as necessary and go to step  23 . If Tan/White wire is okay, go to next step.
  4. Check for short or open in the power and ground circuits to LFPWS. See appropriate wiring diagram in MEMORY SYSTEMS article. Repair as necessary and go to step  23 . If power and ground circuits to LFPWS are okay, go to next step.
  5. Replace LFPWS. Repair as necessary and go to step  23 .
  6. Turn ignition switch to OFF position. Disconnect Left Front Door Module (LFDM) 20-pin connector C1. Turn ignition switch to RUN position. Using DVOM, measure voltage between ground and LFDM connector C1 terminal No. 15 (Tan/White wire). If battery voltage exists, go to step  8 . If battery voltage does not exist, go to next step.
  7. Turn ignition switch to OFF position. Using DVOM, measure resistance between ground and LFDM connector C1 terminal No. 15 (Tan/White wire). If resistance is 0-2 ohms, go to step  9 . If resistance is not 0-2 ohms, go to next step.
  8. Disconnect LFPWS connector. Using DVOM, measure voltage between ground and LFDM connector C1 terminal No. 15 (Tan/White wire). If battery voltage exists, go to step  18 . If battery voltage does not exist, go to step  5 .
  9. Disconnect LFPWS connector. Using DVOM, measure resistance between ground and LFDM connector C1 terminal No. 15 (Tan/White wire). If resistance is 0-2 ohms, go to step  18 . If resistance is not 0-2 ohms, go to step  5 .
  10. Turn ignition switch to RUN position. Using DVOM, measure voltage between ground and LFDM connector C1 terminal No. 6 (Tan/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, go to step  12 .
  11. Turn ignition switch to OFF position. Using DVOM, measure resistance between ground and LFDM connector C1 terminal No. 6 (Tan/White wire). If resistance is 0-2 ohms, go to step  15 . If resistance is not 0-2 ohms, go to step  19 .
  12. Disconnect Right Front Door Module (RFDM). Using DVOM, measure voltage between ground and LFDM connector C1 terminal No. 6 (Tan/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, go to step  20 .
  13. Disconnect Left Rear Door Module (LRDM). Using DVOM, measure voltage between ground and LFDM connector C1 terminal No. 6 (Tan/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, go to step  21 .
  14. Disconnect Right Rear Door Module (RRDM). Using DVOM, measure voltage between ground and LFDM connector C1 terminal No. 6 (Tan/White wire). If battery voltage exists, go to step  18 . If battery voltage does not exist, go to step  22 .
  15. Disconnect Right Front Door Module (RFDM). Using DVOM, measure resistance between ground and LFDM connector C1 terminal No. 6 (Tan/White wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step  20 .
  16. Disconnect Left Rear Door Module (LFDM). Using DVOM, measure resistance between ground and LFDM connector C1 terminal No. 6 (Tan/White wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step  21 .
  17. Disconnect Right Rear Door Module (RRDM). Using DVOM, measure resistance between ground and LFDM connector C1 terminal No. 6 (Tan/White wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step  22 .
  18. Repair short in Tan/White wire. See WIRING DIAGRAMS in MEMORY SYSTEMS article. Repair as necessary and go to step  23 .
  19. Replace LFDM. See DOOR CONTROL MODULE  under REMOVAL & INSTALLATION. After repair, go to step  23 .
  20. Replace RFDM. See DOOR CONTROL MODULE  under REMOVAL & INSTALLATION. After repair, go to step  23 .
  21. Replace LRDM. See DOOR CONTROL MODULE  under REMOVAL & INSTALLATION. After repair, go to step  23 .
  22. Replace RRDM. See DOOR CONTROL MODULE  under REMOVAL & INSTALLATION. After repair, go to next step.
  23. Turn ignition switch to OFF position. Reconnect all previously disconnected components and connectors. Turn ignition switch to RUN position. Clear any DTCs. Perform DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
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