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P184A




DTC P181C-P181F, P183A-P183E, P184A, or P184B

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC P181C
- Internal Mode Switch 2 R1 Circuit Low Voltage

DTC P181D
- Internal Mode Switch 2 R1 Circuit High Voltage

DTC P181E
- Internal Mode Switch 2 R2 Circuit Low Voltage

DTC P181F
- Internal Mode Switch 2 R2 Circuit High Voltage

DTC P183A
- Internal Mode Switch 2 D1 Circuit Low Voltage

DTC P183B
- Internal Mode Switch 2 D1 Circuit High Voltage

DTC P183C
- Internal Mode Switch 2 D2 Circuit Low Voltage

DTC P183D
- Internal Mode Switch 2 D2 Circuit High Voltage

DTC P183E
- Internal Mode Switch 2 - Invalid Range

DTC P184A
- Internal Mode Switch 2 S Circuit Low Voltage

DTC P184B
- Internal Mode Switch 2 S Circuit High Voltage

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 nine 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 module is high when the switch is open and low when the switch is closed to ground.

Conditions for Running the DTC

* The ignition is ON.
* Ignition voltage is greater than 6.0 volts.

Conditions for Setting the DTC

The IMS Direction Signal state does not match for the selected gear for 3 seconds.

Action Taken When the DTC Sets

DTCs P181C, P181D, P181E, P181F, P183A, P183B, P183C, P183D, P183E, P184A and P184B are Type B DTCs.

Conditions for Clearing the DTC

DTCs P181C, P181D, P181E, P181F, P183A, P183B, P183C, P183D, P183E, P184A and P184B are Type B DTCs.

Diagnostic Aids

* The direction IMS assembly can be damaged by electric current exceeding 25 mA. Test the IMS assembly for an open condition whenever a short to voltage condition is observed.
* The direction IMS is a non-serviceable part of the manual shift shaft position switch.

Reference Information
Schematic Reference

Hybrid Controls Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information
Special Tools

* DT-47825-10 Jumper Harness
* DT-48493 Jumper Harness

Circuit/System Verification

Test for correct operation of the Direction IMS in every range selection. Refer to Typical Scan Tool Data.

If the IMS operation matches the logic table, the system is functioning normally.

Circuit/System Testing

1. Disconnect the transmission X176 24-way connector. Ignition ON. The scan tool Direction IMS parameter should display HIGH for the R1, R2, D1, D2 and S signal circuit displays.

• If a signal displays LOW, disconnect the PIM connector X1 and test the circuit for a short to ground.
• If the circuit tests normal, replace the PIM.

2. Install DT-48493 to the vehicle harness connector X176. Verify that a test lamp illuminates between the direction IMS switch ground circuit and battery positive.

• If the test lamp does not illuminate, disconnect PIM connector X1 and test the ground circuit for an open, high resistance or short to voltage condition.
• If the circuit tests normal, replace the PIM.

3. Connect a 3-amp fused jumper wire between each Direction IMS signal circuit at DT-48493 and the ground circuit terminal. The scan tool parameter should display LOW for each signal circuit when grounded.

• If a scan tool parameter always displays HIGH, disconnect PIM connector X1 and test the circuit for an open, high resistance or short to voltage condition.
• If the circuit tests normal, replace the PIM.

4. Disconnect the transmission 16-way X1 connector. Install DT-47825-10 to the vehicle harness. Connect a 3-amp fused jumper wire between the Starter signal circuit terminal and ground. The scan tool parameter should display LOW when the signal circuit is grounded.

• If the scan tool parameter always displays HIGH, disconnect PIM connector X1 and test the circuit for an open, high resistance or short to voltage condition.
• If the circuit tests normal, replace the PIM.

Important: The remaining diagnostic steps test the internal transmission components and circuits. The automatic transmission fluid pan assembly must be removed in order to perform the diagnostic tests.


5. Disconnect the IMS connector at the switch.

Important: Connect one end of the DT-48493 to the transmission connector. Use the other end as the terminal testing point.


• Test the direction signal circuits and the ground circuit between the IMS and the transmission 24-way X176 connector for a short to ground, open, high resistance or short to voltage condition.

Important: Connect one end of the DT-47825-10 to the transmission connector. Use the other end as the terminal testing point.


• Test the Starter signal circuit between the IMS and the transmission 16-way X1 connector for a short to ground, open, high resistance or short to voltage condition. The TCM is a pass-through of the Starter signal circuit and should be tested as a typical circuit path.
• If the circuit, including the TCM, tests normal, replace the IMS switch.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.

* Control Module References (Programming and Relearning) for PIM or TCM replacement, setup, and programming.
* Manual Shift Shaft Position Switch Replacement (Service and Repair).
* Transmission Control Wiring Harness Extension Harness Removal (5. Transmission Control Wiring Harness Extension Harness Removal).

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