2010 Cadillac CTS Sedan AWD V6-3.0L Page 1524

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1524

DTC P0621 is a C type DTC.

Reference Information

Schematic Reference

Starting and Charging Schematics (See: Starting and Charging/Diagrams/Electrical Diagrams)

Connector End View Reference

Component Connector End Views (See: Diagrams/Connector Views)

Description and Operation

Charging System Description and Operation (See: Starting and Charging/Charging System/Description and Operation)

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)

* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)

* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit

Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code

(DTC) Type Definitions)

Scan Tool Reference

Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information

Circuit/System Testing

LSA or LF1 Engine

1. Verify that a test lamp illuminates between the generator B+ and ground.

瀚慖f the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

2. Ignition OFF, disconnect the X1 harness connector at the generator.

3. Ignition ON, test for 4.5-5.5 V between the control circuit terminal 1 and ground.

瀚慖f greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.

瀚慖f less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal replace

the ECM.

4. If the circuits test normal, replace the generator.

LLT Engine

1. Verify that a test lamp illuminates between the generator B+ X2 and ground.

瀚慖f the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

2. Ignition OFF, disconnect the X1 harness connector at the generator.

3. Ignition ON, test for less than 1 V between the control circuit terminal 1 and ground.

瀚慖f greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Engine running, test for greater than 3.5 V between the control circuit terminal 1 and ground.

瀚慖f less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal replace

the ECM.

5. If the circuits test normal, replace the generator.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Generator Replacement (LF1/LLT) (See: Starting and Charging/Charging System/Alternator/Service and Repair)Generator Replacement

(LSA) (See: Starting and Charging/Charging System/Alternator/Service and Repair)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming