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Pinpoint Test C: Transmission Control (TC) Switch Is Not Operating Correctly

  1. C1 CHECK SMART JUNCTION BOX (SJB) FUSE F20 (10A) 
    • Key in OFF position.
    • Check fuse: SJB F20 (10A)
    • Is the resistance less than 5 ohms? 
    1. YES  : REINSTALL the fuse. Go to  C3 .
    2. NO  : INSTALL a new fuse. TEST the system for normal operation. If the fuse fails again, go to  C2 .
  2. C2 CHECK THE CIRCUIT FOR A SHORT TO GROUND 
    • Disconnect: Powertrain Control Module (PCM) C175b
    • Inspect for damaged or pushed-out pins, corrosion or loose wires. Repair as necessary.
      • Fig 1: Measuring Resistance Between PCM C175B-29 & Ground
      GF0027503Courtesy of FORD MOTOR CO.
    • Measure the resistance between PCM C175b-29 and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  C3.
    2. NO  : REPAIR circuit. TEST the system for normal operation.
  3. C3 CHECK THE TC SWITCH CIRCUIT FOR VOLTAGE 
    • Disconnect: PCM C175b
    • Inspect for damaged or pushed-out pins, corrosion or loose wires. Repair as necessary.
    • Leave PCM disconnected
    • Key in ON position.
      • Fig 2: Measuring Voltage Between PCM C175B-29 & Ground
      GF0027504Courtesy of FORD MOTOR CO.
    • Measure the voltage between PCM C175b-29 and ground while cycling the TC switch several times.
    • Does the voltage cycle? 
    1. YES  : INSTALL a new PCM. TEST the system for normal operation.
    2. NO  : Go to  C4.
  4. C4 CHECK THE CIRCUIT FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: Smart Junction Box (SJB) C2280c
    • Disconnect: Selector Lever C2008
    • Inspect both ends for damaged or pushed-out pins, moisture, corrosion or loose wires. Repair as necessary.
      • Fig 3: Measuring Resistance Between SJB C2280C-12 & Selector Lever C2008-1, Harness Side
      GF0027505Courtesy of FORD MOTOR CO.
    • Measure the resistance between SJB C2280c-12 and selector lever C2008-1, harness side.
      • Fig 4: Measuring Resistance Between PCM C175B-29 & Selector Lever C2008-2, Harness Side
      GF0027506Courtesy of FORD MOTOR CO.
    • Measure the resistance between PCM C175b-29 and selector lever C2008-2, harness side.
    • Is the resistance less than 5 ohms for both circuits? 
    1. YES  : Go to  C5.
    2. NO  : REPAIR open circuit. RECONNECT all components. TEST the system for normal operation.
  5. C5 CHECK THE CIRCUIT FOR A SHORT TO POWER 
      Fig 5: Measuring Voltage Between PCM C175B-29 & Ground
      GF0027507Courtesy of FORD MOTOR CO.
    • Measure the voltage between PCM C175b-29 and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : INSTALL a new transmission control switch. RECONNECT all components. TEST the system for normal operation.
    2. NO  : REPAIR circuit. TEST the system for normal operation.
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