Diagnostic Procedure

2000 Cadillac DeVille DHSSECTION Diagnostic Procedure
  1. If power seats diagnostic system check was performed, go to next step. If power seats diagnostic system check was not performed, go to POWER SEATS DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC TESTS.
  2. Connect scan tool to Data Link Connector (DLC). See Figure . Turn ignition on. Using scan tool, select MEMORY SEAT MODULE data list. Monitor CURRENT parameter. Operate driver's power seat switch in all directions. If CURRENT parameter is greater than 81 amps, go to next step. If CURRENT parameter is less than 81 amps, check for intermittent or poor connections at switch.
  3. Disconnect suspect motor connector that indicated greater than 81 amps. Operate suspect motor switch in both directions. Monitor CURRENT parameter. If CURRENT parameter is greater than 81 amps, go to next step. If CURRENT parameter is less than 81 amps, go to step  5 .
  4. Check for short to ground in suspect motor circuits between switch and motor. See WIRING DIAGRAMS  . If circuit is okay, go to step  6 . If faulty circuit is found and repaired, go to step  9 .
  5. Check for poor connections at suspect seat motor connector. If connections are okay, go to step  7 . If faulty connections are found and repaired, go to step  9 .
  6. Check for poor connections at Memory Seat Module (MSM) connector. If circuit is okay, go to step  8 . If faulty circuit is found and repaired, go to step  9 .
  7. Replace suspect seat motor. See SEAT MOTORS under REMOVAL & INSTALLATION in POWER SEATS - DEVILLE article. After repairs, go to step  9 .
  8. Replace MSM. See MEMORY SEAT MODULE  under REMOVAL & INSTALLATION. After repairs, go to next step.
  9. Use scan tool to clear DTCs. Recheck driver's power seat operation. Recheck for DTC. If DTC resets, go to step  2 . If DTC does not reset, repair is complete.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.