Diagnostic Aids
A low voltage DTC in multiple modules indicates a concern in the charging system.
Reference Information
Schematic Reference
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for greater than 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
* ABS Description and Operation (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Description and
Operation/ABS Description and Operation) for less than 3900 kg (8600 lb) GVW
* ABS Description and Operation (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Description and
Operation/ABS Description and Operation) for greater than 3900 kg (8600 lb) GVW
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Engine running, accessories OFF, measure and record the voltage at the battery voltage at the battery terminals. The voltage should be
between 12.6 and 15.0 V.
锟斤拷If not within the specified range, refer to Charging System Test (See: Starting and Charging/Testing and Inspection/Component Tests
and General Diagnostics/Charging System Test).
2. Observe the scan tool EBCM Battery Voltage Signal parameter. The reading should be between 12.6 and 15.0 Volts.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 Ohms between the ground
circuit terminals listed below and ground.
* Terminal 11 (JL4)
* Terminal 38 (w/o JL4)
锟斤拷If greater than the specified range, test the ground circuit for an open/high resistance.
3. Verify that a test lamp illuminates between the B+ circuit terminals listed below and ground.
* Terminal 1 (JL4)
* Terminal 25 (w/o JL4)
锟斤拷If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. If all circuits test normal, replace the EBCM.
