Self-Diagnostic System

NOTE: This procedure DOES NOT cover Motorhomes.

NOTE: Generic Electronic Module (GEM) may also be referred to as Central Timer Module (CTM).

Connect New Generation Star (NGS) or Worldwide Diagnostic System (WDS) tester to Data Link Connector (DLC). DLC is a 16-pin connector located below center of instrument panel. See Fig 1. Using NGS/WDS tester, perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST under SELF-DIAGNOSTIC SYSTEM in MODULE COMMUNICATIONS NETWORK - EXCURSION & F250-F550 SUPER DUTY PICKUPS article.

If NGS/WDS tester displays CKT70, CKT914 or CKT915 = ALL ECUS NO RESP/NOT EQUIP, diagnose module communications problem. See SELF-DIAGNOSTIC SYSTEM in MODULE COMMUNICATIONS NETWORK - EXCURSION & F250-F550 SUPER DUTY PICKUPS article.

If NGS/WDS tester displays NO RESP/NOT EQUIP for GEM, perform TEST A: NO SCAN TOOL COMMUNICATION WITH GENERIC ELECTRONIC MODULE under SYSTEM TESTS.

If NGS/WDS tester displays SYSTEM PASSED, retrieve and record continuous DTCs. Erase continuous DTCs. Perform Generic Electronic Module (GENERIC ELECTRONIC MODULE) self-test. If GEM DTCs related to instrument panel are retrieved, perform appropriate test. See GENERIC ELECTRONIC MODULE DIAGNOSTIC TROUBLE CODE INDEX table. If no instrument panel-related DTCs are retrieved, diagnose by symptom. See SYMPTOM INDEX table under SYSTEM TESTS. For GEM DTCs not covered in this article, see MODULE COMMUNICATIONS NETWORK - EXCURSION & F250-F550 SUPER DUTY PICKUPS article.

GENERIC ELECTRONIC MODULE DIAGNOSTIC TROUBLE CODE INDEX

DTC ⁽¹⁾

Description

Perform Test

B1323

Door Ajar Indicator Circuit Failure

B1325

Door Ajar Indicator Circuit Short To Power

B1342

ECU Defective

⁽²⁾

B1426

Seat Belt Warning Indicator Circuit Short To Power

B1428

Seat Belt Indicator Circuit Failure

C1125

Brake Fluid Level Sensor Input Circuit Failure

C1189

Brake Fluid Level Sensor Input Circuit Short To Ground

C1223

Brake Indicator Warning Output Circuit Failure

C1225

Brake Indicator Warning Output Circuit Short To Power

C1446

Park Brake Switch Circuit Failure

⁽¹⁾	Codes listed in this table are only for testing covered in this article. For GEM DTCs not covered in this article, see MODULE COMMUNICATIONS NETWORK - EXCURSION & F250-F550 SUPER DUTY PICKUPS article.

⁽²⁾	Using NGS/WDS tester, clear DTCs. Retrieve DTCs. If B1342 is retrieved again, replace GEM. See REMOVAL & INSTALLATION .

Fig 1: Identifying Data Link Connector Terminals

Courtesy of FORD MOTOR CO.