2010 Cadillac CTS Sedan AWD V6-3.0L Page 1774

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1774

Circuit/System Description

There are 2 ignition voltage circuits supplied to the engine control module (ECM). The first ignition circuit is provided by the engine controls

ignition relay, or the powertrain relay, through a fuse. This ignition voltage circuit supplies power to all the internal ECM circuits associated with

the throttle actuator control (TAC) operation. The second ignition voltage circuit is supplied by the ignition 1 relay through a fuse, and is used to

power the remaining internal ECM circuits. If the ECM detects a voltage difference between the 2 ignition voltage circuits, DTC P1682 will set.

Conditions for Running the DTC

* The ignition is ON.

* System voltage is more than 6 V.

* The powertrain relay is commanded ON.

* DTC P1682 runs continuously.

Conditions for Setting the DTC

The ECM detects that the voltage level difference is greater than 3 V between the 2 ignition voltage circuits for less than 1 s.

Action Taken When the DTC Sets

DTC P1682 is a Type A DTC.

Conditions for Clearing the DTC

DTC P1682 is a Type A DTC.

Reference Information

Schematic Reference

* Engine Controls Schematics (LLT) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls

Schematics (LF1) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)

* Power Distribution Schematics (See: Diagrams/Electrical Diagrams/Starting and Charging/Power and Ground Distribution/System

Diagram/Power Distribution Schematics)

Connector End View Reference

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

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)

* Electrical Center Identification Views (See: Maintenance/Fuses and Circuit Breakers/Fuse/Application and ID)

* Probing Electrical Connectors (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Probing Electrical

Connectors)

* 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 Verification

Note: On the scan tool, the powertrain relay is referred to as the EC ignition relay.

1. If DTCs P0685 or P0690 are set diagnose those DTCs first.

2. Ignition ON, observe the scan tool Ignition 1 Signal and the EC Ignition Relay Feedback Signal parameters. There should be no more than 3

V difference between the two parameters.

3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed

from the Freeze Frame/Failure Records data.

Circuit/System Testing

Note: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.