2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2459
Transmission Internal Mode Switch Logic
Circuit/System Description
The automatic transmission manual shift shaft position switch assembly, also called the internal mode switch (IMS) assembly, is a dual sliding
contact switch attached to the control valve body within the transmission. The 9 outputs from the switch indicate which position is selected by the
transmission manual shaft. Four outputs (A, B, C, P) are range selection inputs to the transmission control module (TCM). Five outputs (R1, R2,
D1, D2, S) are direction selection inputs to the hybrid powertrain control module (HPCM). The input voltage at the modules is high when the
switch is open and low when the switch is closed to ground. The state of each input is displayed on the scan tool as IMS Range and IMS Direction.
The IMS Range input parameters represented are transmission range signal A, signal B, signal C, and signal P. The IMS Direction input parameters
represented are transmission direction signal R1, signal R2, signal D1, signal D2, and signal Start.
Conditions for Running the DTC
* No OSS DTCs P0722 or P077B.
* The system voltage is 11-18 volts.
P182E
* The engine run time is greater than 5 seconds.
* The system voltage is 11-18 volts.
* The vehicle speed is less than 200 km/h (124 mph) for 5 seconds.
Conditions for Setting the DTC
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
