Pinpoint Test C: The Transmission Control Switch Is Inoperative

WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

C1 CHECK THE CIRCUIT FOR VOLTAGE
- Key in OFF position.
- Disconnect: Brake Shift Interlock Module.
- Key in ON position.
- Measure the voltage between brake shift interlock module pin 4, harness side and ground.
  
  Fig 1: Checking Circuit For Voltage
- Is the voltage greater than 10 volts?
Yes : GO to C2.

No : REPAIR the circuit. TEST the system for normal operation.
C2 CHECK THE TRANSMISSION CONTROL SWITCH
- While cycling the transmission control switch, measure the resistance between brake shift interlock module pin 4 and pin 1, component side.
  
  Fig 2: Checking Transmission Control Switch
- Does the resistance change from greater than 10,000 ohms to less than 5 ohms?
Yes : GO to C3.

No : INSTALL a new brake shift interlock module. TEST the system for normal operation.
C3 CHECK THE CIRCUIT FOR AN OPEN
- Key in OFF position.
- Disconnect: Powertrain Control Module (PCM).
- Measure the resistance between brake shift interlock module pin 1 and the PCM connector pin C29.
- Is the resistance less than 5 ohms?
Yes : GO to C4.

No : REPAIR the circuit. TEST the system for normal operation.
C4 CHECK THE CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between PCM connector pin C29 and chassis ground.
- Is the resistance greater than 10,000 ohms.
Yes : GO to C5.

No : REPAIR the circuit. TEST the system for normal operation.
C5 CHECK THE CIRCUIT FOR A SHORT TO VOLTAGE
- Measure the voltage between PCM connector pin C29 and chassis ground.
- Is voltage present?
Yes : REPAIR the circuit. TEST the system for normal operation.

No : REFER to the INTRODUCTION - GASOLINE .