Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P1824: Internal Mode Switch P Circuit High VoltageDTC P182A: Internal Mode Switch A Circuit Low Voltage
DTC P182B: Internal Mode Switch B Circuit Low Voltage
DTC P182C: Internal Mode Switch B Circuit High Voltage
DTC P182D: Internal Mode Switch P Circuit Low Voltage
DTC P182E: Internal Mode Switch-Invalid Range
DTC P182F: Internal Mode Switch C Circuit High Voltage
DTC P1838: Internal Mode Switch A Circuit High Voltage
DTC P1839: Internal Mode Switch C Circuit Low Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Transmission Range Signal A | P182A | P1838 | P1838 | P182E |
Transmission Range Signal B | P182B | P182C | P182C | P182E |
Transmission Range Signal C | P1839 | P182F | P182F | P182E |
Transmission Range Signal P | P182D | P1824 | P1824 | P182E |
Ground | -- | P182A, P182C, P182F, P1838 | -- | P182E |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
Operating Conditions: Ignition ON, range selector in Park | ||||
Transmission Range Signal A | LOW | LOW | HI | HI |
Transmission Range Signal B | HI | LOW | HI | HI |
Transmission Range Signal C | HI | LOW | HI | HI |
Transmission Range Signal P | LOW | LOW | HI | HI |
HI = 12 volts LOW = 0 volts | ||||
Transmission Internal Mode Switch Logic
Gear Selector Position | Signal A | Signal B | Signal C | Signal P |
|---|---|---|---|---|
Park (P) | LOW | HI | HI | LOW |
Reverse (R) | LOW | LOW | HI | HI |
Neutral (N) | HI | LOW | HI | LOW |
Drive (D) | HI | LOW | LOW | HI |
Manual (M) | HI | HI | LOW | LOW |
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
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
Test for the correct operation of the IMS. Refer to Transmission Internal Mode Switch Logic .
| ⇒ | If the IMS operation matches the IMS logic table, the system if functioning normally. |
Circuit/System Testing
- 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.
- 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. With a scan tool, ensure that each signal circuit displays LOW when connected to ground.
- Connect the IMS harness connector to the control solenoid (w/body and TCM) valve assembly. Disconnect the IMS connector. The scan tool IMS A/B/C/P parameter should display HI for all 4 signal circuits.
- Connect a 3-amp fused jumper wire between each transmission range signal circuit at the IMS connector harness and ground. With a scan tool, ensure that each signal circuit displays LOW when connected to ground.
| ⇒ | If a signal circuit displays LOW, replace the control solenoid (w/body and TCM) valve assembly. |
| ⇒ | If a signal circuit remains HI when connected to ground, replace the control solenoid (w/body and TCM) valve assembly. |
| ⇒ | If a signal circuit displays LOW, replace the IMS jumper harness. |
| ⇒ | If a signal circuit remains HI when connected to ground, replace the IMS harness. |
| ⇒ | If a signal circuit other than the circuit being grounded displays LOW, replace the IMS harness. |
| ⇒ | If all circuits test normal, replace the IMS. |
Component Testing
IMS Circuits | Park | Reverse | Neutral | Drive 4 | Drive 3 | Drive 2 | Drive 1 |
|---|---|---|---|---|---|---|---|
Direction Switch Operating Conditions: Ignition ON, range selector in appropriate gear | |||||||
Transmission Direction Signal R1 | HI | LOW | LOW | HI | HI | HI | HI |
Transmission Direction Signal R2 | LOW | HI | HI | LOW | LOW | LOW | LOW |
Transmission Direction Signal D1 | HI | HI | LOW | LOW | LOW | LOW | LOW |
Transmission Direction Signal D2 | LOW | LOW | HI | HI | HI | HI | HI |
Transmission Direction Signal Start | LOW | HI | LOW | HI | HI | HI | HI |
IMS Circuits | Park | Reverse | Neutral | Drive 4 | Drive 3 | Drive 2 | Drive 1 |
|---|---|---|---|---|---|---|---|
Range Switch Operating Conditions: Ignition ON, range selector in appropriate gear | |||||||
Transmission Range Signal A | LOW | LOW | HI | HI | HI | LOW | LOW |
Transmission Range Signal B | HI | LOW | LOW | LOW | HI | HI | LOW |
Transmission Range Signal C | HI | HI | HI | LOW | LOW | LOW | LOW |
Transmission Range Signal P | LOW | HI | LOW | HI | LOW | HI | LOW |
Always HI status: Open/short to voltage condition Always LOW status: Short to ground condition | |||||||
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Important: Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection for the following components before replacing the components.
| • | Manual Shift Shaft Position Switch Replacement for IMS replacement. |
| • | Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming. |
| • | Wiring Harness Replacement for automatic transmission control wiring harness extension harness assembly replacement. |
