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Theft Deterrent Module Diagnostic System Check

NOTE: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed. The presence of DTC P0601, P0602, P0603, P0604, P0606 or P1621 indicates an internal fault in the Powertrain Control Module (PCM). The presence of DTC B1000, B1004, B1007, or B1009 indicates an internal module fault.
  1. Connect scan tool. Turn ignition on. If scan tool powers up, go to next step. If scan tool does not power up, see TEST A: SCAN TOOL DOES NOT POWER UP  under SYSTEM TESTS.
  2. Turn ignition on. Try to establish communication with Driver's Door Module (DDM), Left Middle Door Module (LMDM) with RPO code V4U, Right Middle Door Module (RMDM) Left Rear Door Module (LRDM), Right Rear Door Module (RRDM), Powertrain Control Module (PCM), Dash Integration Module (DIM), Instrument Panel Cluster (IPC), Rear Integration Module (RIM) and Remote Control Door Lock Actuator (RCDLR). If scan tool communicates with all modules listed, go to next step. If scan tool does not communicate with all modules listed, go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE  under SYSTEM TESTS.
  3. Cycle ignition switch through all positions. Observe CLASS 2 POWER MODE parameter under DIAGNOSTIC CIRCUIT CHECK on scan tool. If displayed CLASS 2 POWER MODE parameter matches actual ignition switch position, go to next step. If displayed CLASS 2 POWER MODE parameter does not match actual ignition switch position, see TEST C: POWER MODE MISMATCH  under SYSTEM TESTS.
  4. Select display DTC function on scan tool for modules listed in step  2. If scan tool displays any DTCs, go to next step. If scan tool does not display any DTCs, see ANTI-THEFT SYSTEMS - DEVILLE article for further diagnosis.
  5. If scan tool does not display any DTCs that begin with "U", go to next step. If scan tool displays any DTCs that begin with "U", see TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE  under SYSTEM TESTS.
  6. If scan tool displays DTC P0601, P0602, P0603, P0604, P0606 or P1621, repair DTCs as necessary. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 4.6L DEVILLE, ELDORADO & SEVILLE article in ENGINE PERFORMANCE. If scan tool does not display any of the codes listed, go to next step.
  7. If scan tool does not display DTC B1007 or B1009, go to next step. If scan tool displays DTC B1007 or B1009, see DIAGNOSTIC TROUBLE CODE DEFINITIONS .
  8. If scan tool displays DTC B1327, see DIAGNOSTIC TROUBLE CODE DEFINITIONS in GENERATORS & REGULATORS - DEVILLE article in STARTING & CHARGING SYSTEMS. If scan tool does not display B1327, diagnose any other DTCs that exist. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
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