2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 1977
Any one or more of the following conditions:
* The IMS signal circuit A, B, or P are Low in Park for greater than 8 seconds.
* The IMS signal circuit A is Low in D for 8 seconds.
* The IMS signal circuit C is High in D for 8 seconds.
* The TCM detects an invalid range from the IMS for 3.25 seconds.
* The IMS signal circuit C is high in D for greater than 8 seconds.
* Park/Neutral Switch equals P/N and the IMS state is not Park or Neutral, or the Park/Neutral switch is not Park or Neutral and the IMS state
equals Park or Neutral for 4 seconds.
* Or the automatic transmission manual shift shaft position switch assembly indicates a transitional state for 8 seconds.
Action Taken When the DTC Sets
* The TCM commands maximum line pressure.
* The TCM turn OFF all solenoids.
* The TCM freezes transmission adaptive functions.
* The TCM defaults the transmission to 3rd gear if the current gear is 1st or 2nd gear, or 3rd gear if the current gear is 4th gear.
Conditions for Clearing the DTC
DTCs P1824, P182A-P182F, P1838, and P1839 are Type B DTCs.
Diagnostic Aids
The IMS connects electrically to the control solenoid (w/body and TCM) valve assembly and is serviced separately from the control solenoid
(w/body and TCM) valve assembly. Inspect the IMS, harness, connector, and control solenoid (w/body and TCM) valve assembly pins for metallic
debris. Use a terminal test kit for any test that requires probing the control solenoid (w/body and TCM) valve assembly harness connector or a
component harness connector. The IMS assembly can be damaged by currents exceeding 2 mA. Test the IMS assembly for an open condition
whenever a short to voltage condition is observed.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Diagrams)
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/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)
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
Test for the correct operation of the IMS. Refer to Transmission Internal Mode Switch Logic (See: Specifications/Mechanical
Specifications/Automatic Transmission/Transaxle/System Specifications/2ML70 - Automatic Transmission/Transmission Internal Mode Switch
Logic).
If the IMS operation matches the IMS logic table, the system if functioning normally.
Circuit/System Testing
1. Disconnect the IMS harness connector at the control solenoid (w/body and TCM) valve assembly. Ignition ON. The scan tool IMS A/B/C/P
parameter should display HI for all 4 signal circuits.
