2010 Cadillac CTS Sedan AWD V6-3.6L Page 1524
Circuit/System Description
The engine control module (ECM) uses the generator turn ON control circuit to control the load of the generator on the engine. A high side driver
in the ECM applies a voltage to the voltage regulator. This controls the voltage regulator to turn the field circuit ON and OFF. The ECM monitors
the state of the generator turn ON control circuit. The ECM should detect low voltage on generator turn on control circuit when the ignition is ON
and the engine is OFF, or when the charging system malfunctions. With the engine running, the ECM should detect high voltage on the generator
turn on control circuit.
Conditions for Running the DTC
* The ignition ON, engine OFF for ignition on test.
* The engine is running for the run test.
Conditions for Setting the DTC
* During the ignition on test, the ECM detects voltage on the generator turn on control circuit for 5 seconds.
* During the run test, the ECM detects low voltage on the generator turn on control circuit for 15 seconds.
Action Taken When the DTC Sets
DTC P0621 is a C type DTC.
Conditions for Clearing the DTC
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.
