Self-Diagnostic System

NOTE: Ensure speedometer and horn systems are operating properly before testing speed control system.

Connect New Generation Star (NGS) tester to Data Link Connector (DLC) located below instrument panel. Using NGS tester, perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST under SELF-DIAGNOSTIC SYSTEM in MODULE COMMUNICATIONS NETWORK - TOWN CAR article. If NGS tester displays CKT914, CKT915 or CKT70=ALL ECUS NO RESP/NOT EQUIP, repair communication concern. See MODULE COMMUNICATIONS NETWORK - TOWN CAR article. If NGS tester displays NO RESP/NOT EQUIP for speed control servo, perform TEST A: NO COMMUNICATION WITH SPEED CONTROL SERVO under SYSTEM TESTS. If NGS tester displays SYSTEM PASSED, retrieve and record continuous DTCs. Erase continuous DTCs. Perform speed control servo self-test. Perform appropriate DTC test in accordance with DTC retrieved. See SPEED CONTROL SERVO DTC INDEX table. Codes listed in table are only for testing covered in this article. For complete DTC listing, see MODULE COMMUNICATIONS NETWORK - TOWN CAR article. If no DTCs are retrieved, repair by symptom. See SYMPTOM INDEX under SYSTEM TESTS.

SPEED CONTROL SERVO DTC INDEX

DTC ⁽¹⁾

Description

Perform Test

B1318

Battery Voltage Low

B1342

ECU Defective

⁽²⁾

C1109

Throttle Position Did Not Return To Idle After Self-Test

C1126

Speed Control Switch Stuck For 2 Minutes Or Longer

C1127

Deactivator Switch Circuit Failure

C1179

Speed Control Cable Slack Failure

⁽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. Perform air suspension/electronic variable orifice steering module self-test. If DTC B1342 is retrieved again, replace air suspension/electronic variable orifice steering module.