Automatic Transmission (6L50/6L80/6L90)
DTC P182E or P1915
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.
DTC Descriptor
DTC P182E
- Internal Mode Switch - Invalid Range
DTC P1915
- Internal Mode Switch Start/Wrong Range
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The internal mode switch (IMS) assembly is a sliding contact switch attached to the control valve body within the transmission. The four inputs to the transmission control module (TCM) from the switch indicate which position is selected by the transmission manual shaft. The input voltage at the TCM 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. The IMS input parameters represented are transmission range signal A, Signal B, signal C, and signal P.
Conditions for Running the DTC
P182E
* No OSS DTCs P0722 or P0723.
* VSS is greater than 16 km/h (10 mph)
P1915
* No OSS DTCs P0722 or P0723.
* The transmission output shaft speed is less than 90 RPM.
Conditions for Setting the DTC
P182E
Any one or more of the following conditions:
* The IMS signal circuit A, B, or P are Low in Park for greater than 1 second.
* The IMS signal circuit A is Low in D6 for 8 seconds.
* The IMS signal circuit C is High in D6 for 8 seconds.
* The TCM detects an invalid range from the IMS for 3.25 seconds.
* The IMS signal circuit C is high in D6 for greater than 8 seconds and the engine torque is greater than 20 Nm (15 lb. ft).
* 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.
P1915
The manual shift shaft switch assembly indicates a transitional state during the following sequence:
* The engine speed is less than 50 RPM for more than 0.25 seconds.
* The engine speed is 50-480 RPM for more than 0.07 seconds.
* The engine speed is greater than 525 RPM for more than 3.25 seconds.
* The transmission input shaft speed is greater than 250 RPM.
Action Taken When the DTC Sets
* DTCs P182E and P1915 are Type A DTCs.
* The TCM commands maximum line pressure.
* The TCM turns OFF all solenoids.
* The TCM freezes transmission adaptive functions.
* The TCM defaults the transmission to third gear if the current gear is 1st, 2nd, or 3rd; or fifth gear if the current gear is 4th, 5th, or 6th gear.
Conditions for Clearing the DTC
DTCs P182E and P1915 are Type A DTCs.
Diagnostic Aids
The IMS is part of a wire harness, which 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 GM-approved 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.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics).
* Connector Repairs (Component Tests and General Diagnostics).
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics).
* Wiring Repairs (Component Tests and General Diagnostics).
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (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 (Transmission Internal Mode Switch Logic).
If the IMS operation matches the IMS logic table, the system is functioning normally.
Circuit/System Testing
1. Disconnect the IMS 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 four signal circuits.
• If a signal circuit displays LOW, the control solenoid (w/body and TCM) valve assembly is faulty.
2. Connect a 3-amp fused jumper wire between each transmission range signal circuit at the control solenoid (w/body and TCM) valve assembly and ground ensuring that the signal circuit displays LOW when connected to ground.
• If a signal circuit remains HI when connected to ground, the control solenoid (w/body and TCM) valve assembly is faulty.
• If the above two tests indicate correct TCM functions, the IMS is faulty.
Component Testing
Repair Instructions
Important: Always perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Important: Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (Control Solenoid Valve and Transmission Control Module Assembly Inspection) for the following components before replacing the components.
* Internal Mode Switch (IMS) Replacement. Refer to Manual Shift Shaft Position Switch Replacement (5L40-E/5L50-E - Automatic Transmission).
* Control Solenoid (w/Body and TCM) Valve Assembly Replacement. Refer to Control Module References (Programming and Relearning).