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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 1614 (Vehicle Dynamic Suspension) >> Diagnostic Tests >> Vehicle Dynamic Suspension >> Pinpoint Tests >> Pinpoint Test G: DTC C1840 - The Scan Tool Indicates Self-Test Failure When Attempting to Carry Out the Self-Test >> Pinpoint Test G: DTC C1840 - The Scan Tool Indicates Self-Test Failure When Attempting To Carry Out The Self-Test

Pinpoint Test G: DTC C1840 - The Scan Tool Indicates Self-Test Failure When Attempting To Carry Out The Self-Test

WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
  1. G1 CHECK THE AIR SUSPENSION SWITCH VOLTAGE 
    • Key in OFF position.
    • Disconnect: Air Suspension Switch C4087
    • Key in ON position.
      • Fig 1: Checking Circuits For Voltage
      GF0013880Courtesy of FORD MOTOR CO.
    • Measure the voltage between air suspension switch C4087-2, circuit 417 (VT/OG), harness side and ground.
    • Is the voltage approximately 5 volts? 
    1. YES  : Go to  G2.
    2. NO  : Go to  G4.
  2. G2 CHECK CIRCUIT 635 (YE) FOR AN OPEN 
    • Disconnect: VDM C2131a
    • Disconnect: VDM C2131b
      • Fig 2: Checking Circuit For Open
      GF0013881Courtesy of FORD MOTOR CO.
    • Measure the resistance between air suspension switch C4087-1, circuit 635 (YE), harness side and VDM C2131b-7, circuit 635 (YE), harness side.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  G3.
    2. NO  : REPAIR circuit 635 (YE). CLEAR the DTCs. REPEAT the self-test.
  3. G3 CHECK CIRCUIT 635 (YE) FOR A SHORT TO GROUND 
      Fig 3: Checking Circuit For Short To Ground
      GF0013882Courtesy of FORD MOTOR CO.
    • Measure the resistance between VDM C2131b-7, circuit 635 (YE), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  G6.
    2. NO  : REPAIR circuit 635 (YE). CLEAR the DTCs. REPEAT the self-test.
  4. G4 CHECK CIRCUIT 417 (VT/OG) FOR AN OPEN 
      Fig 4: Checking Circuit For Open
      GF0013883Courtesy of FORD MOTOR CO.
    • Measure the resistance between air suspension switch C4087-2, circuit 417 (VT/OG), harness side and VDM C2131b-4, circuit 417 (VT/OG).
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  G5.
    2. NO  : REPAIR circuit 417 (VT/OG). CLEAR the DTCs. REPEAT the self-test.
  5. G5 CHECK CIRCUIT 417 (VT/OG) FOR A SHORT TO GROUND 
      Fig 5: Checking Circuit For Short To Ground
      GF0013884Courtesy of FORD MOTOR CO.
    • Measure the resistance between VDM C2131b-4, circuit 417 (VT/OG), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  G6.
    2. NO  : REPAIR circuit 417 (VT/YE). CLEAR the DTCs. REPEAT the self-test.
  6. G6 CHECK THE AIR SUSPENSION SWITCH 
    • Push the air suspension switch to the ON position.
    • Measure the resistance between air suspension switch pin 1, component side and pin 2, component side.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  G7.
    2. NO  : INSTALL a new air suspension switch. REFER to Air Suspension Switch . CLEAR the DTCs. REPEAT the self-test.
  7. G7 VERIFY VDM CONNECTIONS 
    • Check VDM connectors C2131a and C2131b for damage or loose connections.
    • Are the module connections OK? 
    1. YES  : INSTALL a new VDM. REFER to Vehicle Dynamics Module (VDM) .
    2. NO  : REPAIR the VDM connectors. CLEAR the DTCs. REPEAT the self-test.
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