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Pinpoint Test A: SPEED CONTROL IS INOPERATIVE

WARNING: This page is about a different car, the 2005 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.
  1. A1 CHECK CIRCUITS 7-PG24 (YE/BU), 31S-PG1 (BK/BU), AND 31S-PG24 (BK/OG) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Disconnect: Powertrain Control Module (PCM) C175b.
    • Disconnect: Clockspring C218b.
    • Key in ON position.
    • Measure the voltage between the PCM C175b-56, circuit 31S-PG24 (BK/OG), harness side and ground; and between the PCM C175b-57, circuit 7-PG24 (YE/BU), harness side and ground.
      Fig 1: Measuring Voltage Between PCM C175b-56, Circuit 31S-PG24 (BK/OG), Harness Side And Ground; And PCM C175b-57, Circuit 7-PG24 (YE/BU), Harness Side And Ground
      G03997947Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
    • Yes  : REPAIR the circuit(s) in question. CLEAR the DTCs. REPEAT the self-test.
    • No  : GO to  A2.
  2. A2 CHECK CIRCUITS 7-PG24 (YE/BU), 31S-PG1 (BK/BU), AND 31S-PG24 (BK/OG) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Measure the resistance between the PCM C175b-56, circuit 31S-PG24 (BK/OG), harness side and ground; and between the PCM C175b-57, circuit 7-PG24 (YE/BU), harness side and ground.
      Fig 2: Measuring Resistance Between PCM C175b-56, Circuit 31S-PG24 (BK/OG), Harness Side And Ground; And Between PCM C175b-57, Circuit 7-PG24 (YE/BU), Harness Side And Ground
      G03997948Courtesy of FORD MOTOR CO.
    • Are the resistances greater than 10,000 ohms? 
    • Yes  : GO to  A3.
    • No  : REPAIR the circuit(s) in question. CLEAR the DTCs. REPEAT the self-test
  3. A3 CHECK CIRCUITS 7-PG24 (YE/BU), 31S-PG1 (BK/BU) AND 31S-PG24 (BK/OG) FOR AN OPEN 
    • Measure the resistance between the PCM C175b-56, circuit 31S-PG24 (BK/OG), harness side and the clockspring C218b-3, circuit 31S-PG1 (BK/BU), harness side; and between the PCM C175b-57, circuit 7-PG24 (YE/BU), harness side and the clockspring C218b-4, circuit 7-PG24 (YE/BU), harness side.
      Fig 3: Measuring Resistance Between PCM C175b-56, Circuit 31S-PG24, Harness Side And The Clockspring C218b-3, circuit 31S-PG1, Harness Side; And Between PCM C175b-57, Circuit 7-PG24, Harness Side And Clockspring C218b-4, Circuit 7-PG24 Harness Side
      G03997949Courtesy of FORD MOTOR CO.
    • Are the resistances less than 5 ohms? 
    • Yes  : GO to  A4.
    • No  : REPAIR the circuit(s) in question. CLEAR the DTCs. REPEAT the self-test.
  4. A4 CHECK THE CLOCKSPRING 
    • Remove the driver air bag module. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
    • Disconnect: Upper Clockspring Connector.
    • Measure the resistance between the clockspring C218b pin 3, component side and the upper clockspring connector pin 3, component side; and between the clockspring C218b pin 4, component side and the upper clockspring connector pin 4, component side.
      Fig 4: Measuring Resistance Between Clockspring C218b Pin 3, Component Side And Upper Clockspring Connector Pin 3, Component Side; And Between Clockspring C218b Pin 4, Component Side And Upper Clockspring Connector Pin 4, Component Side
      G03997950Courtesy of FORD MOTOR CO.
    • Are the resistances less than 5 ohms? 
  5. A5 CHECK THE STEERING WHEEL CONTROL HARNESS 
    • Disconnect: Speed Control Switch.
    • Inspect the steering wheel control harness for shorts, opens, or any damage.
    • Is the steering wheel control harness OK? 
    • Yes  : GO to  A6.
    • No  : REPAIR or INSTALL a new steering wheel control harness. INSTALL the driver air bag module. Refer to SUPPLEMENTAL RESTRAINT SYSTEM . CLEAR the DTCs. REPEAT the self-test.
  6. A6 CHECK THE SPEED CONTROL SWITCH 
    • Connect: Speed Control Switch.
    • Measure the resistance between the upper clockspring connector pin 3, harness side and the upper clockspring connector pin 4, harness side while pressing the speed control buttons as follows:
    SPEED CONTROL SWITCH RESISTANCE SPECIFICATION

    Speed Control Switch Resistance Value
    Cancel 114 - 126 ohms
    SET- Between 285 and 315 ohms
    SET+ 570 - 630 ohms
    Resume 1,055 - 1,165 ohms
    On 2,004 - 2,216 ohms
    Off Less than 5 ohms
    Fig 5: Measuring Resistance Between Upper Clockspring Connector Pin 3, Harness Side And Upper Clockspring Connector Pin 4, Harness Side
    G03997951Courtesy of FORD MOTOR CO.
    • Are the speed control switch resistance values OK? 
  7. A7 CHECK FOR CORRECT PCM OPERATION 
    • Disconnect all the PCM connectors.
    • Check for:
      • corrosion
      • pushed-out pins
    • Connect all the PCM connectors and make sure they seat correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    • Yes  : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS . TEST the system for normal operation.
    • No  : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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