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.
