Self-Diagnostic System

Verify customers complaint. Check for blown fuses. Check for loose or corroded connectors and damaged wiring harness. Repair or replace components as necessary.

If all components are okay, connect New Generation Star (NGS) tester to Data Link Connector (DLC), located beneath instrument panel. Using NGS tester, preform data link diagnostics test. See DATA LINK DIAGNOSTIC TEST under SELF-DIAGNOSTIC SYSTEM in MODULE COMMUNICATIONS NETWORK - TOWN CAR article. If NGS tester responds with CKT914 or CKT915=ALL ECUS NO RESP/NOT EQUIP, repair module communications concern. See MODULE COMMUNICATIONS NETWORK article. If NGS tester displays NO RESP/NOT EQUIP for Driver's Door Module (DDM), perform TEST A: NO COMMUNICATION WITH DRIVER'S DOOR MODULE under SYSTEM TESTS.

If NGS tester responds with SYSTEM PASSED, retrieve and record continuous DTCs. Erase continuous DTCs. Using NGS tester, perform DDM self-test. Perform appropriate test in accordance with DTC retrieved. See DRIVER'S DOOR MODULE DTC INDEX table. Codes listed in this table are only for testing covered in this article. For complete DTC listing, see MODULE COMMUNICATIONS NETWORK article. If no DTCs are retrieved, repair by symptom. See SYMPTOM CHART table under SYSTEM TESTS.

DRIVER'S DOOR MODULE DTC INDEX

DTC ⁽¹⁾

Description

Perform Test

B1342

ECU Defective

⁽²⁾

B1402

Driver's Door Window Switch Down Circuit Open

B1549

Power Window Switch Short To Voltage

⁽¹⁾	Codes listed in this table are only for testing covered in this article. For complete DTC listing, see MODULE COMMUNICATIONS NETWORK - TOWN CAR article.

⁽²⁾	Using NGS tester, retrieve and document all continuous DTCs. Perform DDM self-test. If DTC B1342 is retrieved again, replace DDM.