2010 Cadillac CTS Sedan AWD V6-3.6L Page 1792
* Throttle valve that is NOT in the rest position
* Throttle valve that is binding open or closed
* Throttle valve that is free to move open or closed WITHOUT spring pressure
If a condition is found, replace the throttle body assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Throttle Body Assembly Replacement (LF1) (See: Powertrain Management/Fuel Delivery and Air Induction/Throttle Body/Service and
Repair/Removal and Replacement)Throttle Body Assembly Replacement (LLT) (See: Powertrain Management/Fuel Delivery and Air
Induction/Throttle Body/Service and Repair/Removal and Replacement)
With Y41
DTC P1631 (with Y41)
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 P1631
- Theft Deterrent Fuel Enable Signal Not Correct
Circuit/System Description
The remote control door lock receiver (RCDLR) sends the prerelease password to the engine control module (ECM) via the serial data circuit. The
ECM then sends a challenge to the RCDLR. Both the ECM and RCDLR perform a calculation on this challenge. If the calculated response from the
RCDLR equals the calculation performed by the ECM, the ECM will allow vehicle starting.
Conditions for Running the DTC
Ignition is in the ACCESSORY or RUN position.
Conditions for Setting the DTC
The ECM receives an incorrect prerelease password from the RCDLR.
Action Taken When the DTC Sets
* The security indicator will illuminate.
* Vehicle starting will be disabled.
Conditions for Clearing the DTC
* A current DTC P1631 will be when a correct fuel enable password is received.
* A history DTC will be cleared after 40 malfunction-free ignition cycles or when a scan tool is used to clear DTCs.
Reference Information
Schematic Reference
Immobilizer Schematics (See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Diagrams/Electrical Diagrams/Immobilizer
Schematics)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Immobilizer Description and Operation (without Y41) (See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Description and
Operation/Immobilizer Description and Operation (Without Y41))Immobilizer Description and Operation (with Y41) (See: Accessories and
