Diagnostic Routine B

Diagnostic Routine B

Diagnostic Overview

Transmission Control Switch (TCS)

Refer to Wiring Diagram Set 37 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Condition

The TCS (Transmission Control Switch) is a momentary contact switch located on the selector lever. Pressing the TCS (Transmission Control Switch) will engage or disengage the O/D (Overdrive) function of the transmission. When the O/D (Overdrive) is disengaged, the O/D (Overdrive) icon will illuminate OFF on the IPC (Instrument Panel Cluster). Each time the ignition switch is cycled, the transmission will automatically provide O/D (Overdrive) operation regardless of TCS (Transmission Control Switch) position the last time the engine was running.

DTC Fault Trigger Conditions






Pinpoint Test

1. Read and record all DTCs (Diagnostic Trouble Codes).

Is DTC (Diagnostic Trouble Code) P1780 set?






2. Check the BJB (Battery Junction Box) fuse

1. Ignition OFF.

2. Remove the BJB (Battery Junction Box) fuse 38 (15A).

3. Check fuse 38 (15A)

Is the resistance less than 5 ohms?






3. Check for PCM (Powertrain Control Module) DTCs (Diagnostic Trouble Codes).

Is DTC (Diagnostic Trouble Code) P0562 or U0100 set?






4. Check the TCS (Transmission Control Switch) for a short to ground

1. Disconnect floor shifter C3245.

2. Measure the resistance of circuit CET16 (WH/BU) from floor shifter C3245 to ground.





Is the resistance greater than 10,000 ohms?






5. Check the TCS (Transmission Control Switch) for a short to ground

1. Disconnect the TCM (Transmission Control Module) C1750A.

2. Measure the resistance of circuit CET44 (YE/BU) between floor shifter C3245-5 and ground.





Is the resistance greater than 10,000 ohms?






6. Check the TCS (Transmission Control Switch) for an open

1. Disconnect floor shifter C3245.

2. Measure the resistance of circuit CET16 (WH/BU) from floor shifter C3245-6 to BJB (Battery Junction Box) fuse 38.





Is the resistance less than 5 ohms?






7. Check the TCS (Transmission Control Switch) signal input circuit for an open

1. Disconnect the TCM (Transmission Control Module) C1750A.

2. Measure the resistance of circuit CET44 (YE/BU) between floor shifter C3245-5 to the TCM (Transmission Control Module) C1750A-11.





Is the resistance less than 5 ohms?






8. Check the TCS (Transmission Control Switch)

1. Measure the resistance between selector lever C3245-5 and C3245-6 while cycling the TCS (Transmission Control Switch).





Is the resistance less than 5 ohms with the switch pressed and greater than 10,000 ohms when released?






9. Check the TCM (Transmission Control Module)

1. Install fuse 38 (15A).

2. Connect the floor selector C3245.

3. Ignition ON.

4. Measure the voltage on circuit CET44 (YE/BU) at the TCM (Transmission Control Module) C1750A-11 to ground while cycling the TCS (Transmission Control Switch).





Is the voltage greater than 10 volts with the switch pressed, and less than 5 volts with the switch released?