Diagnostic Instructions

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

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Reverse 1 (15)	P181C	P181D	P181D	--
Reverse 2 (16)	P181E	P181F	P181F	--
Drive 1 (17)	P183A	P183B	P183B	--
Drive 2 (18)	P183C	P183D	P183D	--
Start (39)	P184A	P184B	P184B	--
IMS Direction Return (32)	--	P183E	P183E	--

Typical Scan Tool Data

Internal Mode Switch (IMS)

IMS Circuits/Parameter	Selector Position
	Park	Reverse	Neutral	Drive	Manual
Direction Switch Operating Conditions: Ignition ON, range selector in appropriate gear
Direction IMS D1	HIGH	HIGH	LOW	LOW	LOW
Direction IMS D2	LOW	LOW	HIGH	HIGH	HIGH
Direction IMS R1	HIGH	LOW	LOW	HIGH	HIGH
Direction IMS R2	LOW	HIGH	HIGH	LOW	LOW
Direction IMS Start	LOW	HIGH	LOW	HIGH	HIGH
Range Switch Operating Conditions: Ignition ON, range selector in appropriate gear
IMS A	LOW	LOW	HI	HI	HI
IMS B	HI	LOW	LOW	LOW	HI
IMS C	HI	HI	HI	LOW	LOW
IMS P	LOW	HI	LOW	HI	LOW
Always HIGH status: Open/short to voltage condition Always LOW status: Short to ground condition Every status HIGH for either switch indicates an open ground circuit or connector for that portion of the IMS.

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

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

Reference Information

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

Circuit/System Verification

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

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 X175 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 X175 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 after completing the repair.