2010 Cadillac Truck Escalade RWD V8-6.2L Page 2441

2010 Cadillac Truck Escalade RWD V8-6.2L Page 2441

Immobilizer Description and Operation (See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Description and

Operation/Immobilizer Description and Operation)

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

Important: Because of normal system communications between the TDM and ECM, any theft deterrent B-codes must be diagnosed prior

to the diagnosis of P-codes.

Perform the 10-Minute Immobilizer Relearn procedure. Refer to Immobilizer System Component Programming (See: Accessories and Optional

Equipment/Antitheft and Alarm Systems/Testing and Inspection/Programming and Relearning). The ECM should successfully complete the

password learn and the vehicle should start.

If the ECM does not complete the learn or vehicle starting remains disabled, replace the ECM.

Repair Instructions

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

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

P1668

DTC P1668

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptor

DTC P1668

- Generator L-Terminal Control Circuit

Diagnostic Fault Information

Circuit/System Description

The engine control module (ECM) uses the generator turn on signal circuit, or L-terminal 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 signals the voltage regulator to turn the field circuit ON and OFF.

The ECM monitors the state of the generator turn ON signal circuit. The ECM should detect low voltage on generator turn on signal 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 signal circuit. The ECM performs tests to determine the status of the generator turn on signal circuit.

Conditions for Running the DTC

The engine is running.