The transmission range (TR) switch is part of the park/neutral position and back-up lamp switch assembly and is externally mounted on the transmission manual shaft. The TR switch is a multi-signal switch. The transmission control module (TCM) supplies ignition voltage to the TR switch on 4 signal circuits, A, B, C, and P. Each gear selector lever position grounds 1 or more of the switch circuits. In order to determine the gear range selected by the driver, the TCM compares the voltage combinations on the signal circuits to a look-up table stored in TCM memory. The TCM detects the selected gear range by the state change of the switch input. Refer to Transmission Range Switch Logic.

Switch input to the TCM is represented on the scan tool as HI and LOW. HI indicates an ignition voltage signal. LOW indicates a zero voltage signal. The 4 parameters represent transmission range switch signal A, B, C and Parity.

The engine run time is greater than 5 seconds and not in fuel cut-off.

The combination of TR switch signals are invalid for 60 seconds. Refer to Transmission Range Switch Logic.

DTC P0705 is a type C DTC.

DTC P0705 is a type C DTC.

Schematic Reference

Automatic Transmission 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

J 35616 GM-Approved Terminal Test Kit

Start the engine. With the vehicle in PARK and at normal operating temperature, observe the TR Sw. A/B/C/P parameter on the scan tool. The TR Sw. A/B/C/P parameter should display LOW/HIGH/HIGH/LOW.

1. Turn ON the ignition, leaving the engine OFF. Using a scan tool, observe the TR Sw. parameter while selecting each transmission range. The TR Sw. parameter should match each range when selected.

⇒	If the TR Sw. range on the scan tool matches each selected range, test for intermittent conditions.

2. Inspect the park/neutral position (PNP) switch assembly and the shift cable for the following conditions:

⇒	If any of the conditions are found, repair or replace as necessary.

•

Damage

•	Loose or missing mounting hardware

•	Proper adjustment

•	Refer to Park/Neutral Position Switch Replacement.

•	Damaged or stretched cable

•	Proper adjustment

•	Refer to Automatic Transmission Range Selector Lever Cable Replacement.

3. Using the scan tool, observe the TR Sw. A/B/C/P parameter. The parameter should display LOW/HIGH/HIGH/LOW.

⇒	If the scan tool displays HI for all signal states, repair the open or high resistance in the ground circuit for the PNP switch.

4. Turn OFF the ignition. Disconnect the PNP switch connector. Turn ON the ignition, leaving the engine OFF. Observe the TR Sw. A/B/C/P parameter on the scan tool. The scan tool should display HI for all TR Sw. signal circuits.

⇒	If any of the TR Sw. A/B/C/P signal circuits do not display HI, test the affected circuit for a short to ground.

5. Using the J 35616 GM-approved terminal test kit and a DMM, measure the voltage at each TR signal circuit to ground. Each circuit should measure 10-12 volts.

⇒	If the voltage on any of the circuits is less than the specified value, test the affected circuit for an open or high resistance.

⇒	If an open or high resistance is not found, replace the TCM.

6. Turn OFF the ignition. Leaving the PNP switch disconnected, disconnect the TCM harness connector. Using the J 35616 , measure the resistance between each TR signal circuit and all other TR signal circuits. The resistance should be greater than 10K ohms.

⇒	If the resistance is less than 10K ohms, test for a shorted together condition on the TR signal circuits.

⇒	If all circuits and connections test normal, test the PNP switch.

Using the J 35616 , connect a test lamp between battery positive voltage and any of the TR signal circuits at the PNP switch. Referring to Transmission Range Switch Logic will ensure that the test lamp illuminates when the TR signal circuit that is being tested is grounded.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.