Pinpoint Test A: The Speed Control Is Inoperative

1999 Mercury Tracer LS, 4D Sedan, StandardSECTION Pinpoint Test A: The Speed Control Is Inoperative
WARNING: This page is about a different car, the 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
  1. A1 CHECK FOR DTCS 
    • Review the recorded DTCs from the powertrain control module (PCM) self-test.
    • Are any DTCs recorded? 
  2. A2 CHECK THE SPEED CONTROL SWITCH 
    • Disconnect: PCM C175b.
    • Measure the resistance between the PCM C175b-19, circuit 151 (LB/BK), harness side and the PCM C175b-30, circuit 133 (BK), harness side.
      SPEED CONTROL SWITCH RESISTANCE

      Speed Control Switch Resistance Value
      OFF Less than 5 ohms
      SET- 285 - 315 ohms
      SET + 570 - 630 ohms
      RESUME 1,055 - 1,165 ohms
      ON 2,004 - 2,216 ohms
      No switch pressed 4,094 - 4,526 ohms
      Fig 1: Checking The Speed Control Switch
      G03883120Courtesy of FORD MOTOR CO.
    • Are the speed control switch resistance values OK? 
    • Yes  : If equipped with automatic transmission, GO to A3.

      If equipped with manual transmission, GO to  A5.

    • No  : INSTALL a new speed control switch. REFER to SPEED CONTROL SWITCH .. CLEAR the DTCs. REPEAT the self-test.
  3. A3 CHECK THE DIGITAL TRANSMISSION RANGE (TR) SENSOR 
    • Connect: PCM C175b.
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: PID Data Monitor and Record.
    • Monitor the TR sensor PID.
    • Select DRIVE.
    • Does the PID value agree with the transmission range selector lever position? 
  4. A4 CHECK THE DIGITAL TR SENSOR FOR CORRECT ALIGNMENT 
  5. A5 CHECK THE CLUTCH PEDAL POSITION (CPP) SWITCH 
    • While pressing and releasing the clutch pedal, measure the resistance between the PCM C175b-32, circuit 306 (TN/LB), harness side and ground.
      Fig 2: Checking Continuity Between Connector And Ground
      G03924168Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms with the clutch pedal pressed, and less than 5 ohms with the clutch pedal released? 
    • Yes  : GO to  A8.
    • No  : GO to A6.
  6. A6 CHECK CIRCUIT 306 (TN/LB) FOR AN OPEN 
    • Disconnect: CPP Switch C277.
    • Measure the resistance between the PCM C175b-32, circuit 306 (TN/LB), harness side and the CPP switch C277-4, circuit 306 (TN/LB), harness side.
      Fig 3: Checking Circuit 306 (TN/LB) Open
      G03924169Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes  : GO to A7.
    • No  : REPAIR the circuit. TEST the system for normal operation.
  7. A7 CHECK CIRCUIT 570 (BK/WH) FOR AN OPEN 
    • Measure the resistance between the CPP switch C277-3, circuit 570 (BK/WH), harness side and ground.
      Fig 4: Checking Circuit 570 (BK/WH) For An Open
      G03924170Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes  : INSTALL a new CPP switch. TEST the system for normal operation.
    • No  : REPAIR the circuit. TEST the system for normal operation.
  8. A8 CHECK THE PARKING BRAKE WARNING INDICATOR 
    • Key in ON position.
    • While observing the parking brake warning indicator, apply and release the parking brake.
    • Does the parking brake warning indicator operate correctly? 
    • Yes  : GO to A9.
    • No  : REFER to INSTRUMENT CLUSTER to diagnose the parking brake warning indicator.
  9. A9 CHECK THE VEHICLE SPEED 
    NOTE: This step may require an assistant.
    • Enter the following diagnostic mode on the diagnostic tool: Anti-lock Brake System (ABS) Wheel Speed PID.
    • Monitor and record the ABS module wheel speed PID while driving the vehicle at 48 km/h (30 mph) as indicated on the speedometer.
    • Enter the following diagnostic mode on the diagnostic tool: PCM Vehicle Speed PID.
    • Monitor and record the PCM vehicle speed PID while driving the vehicle at 48 km/h (30 mph).
    • Does the speed indicated by the ABS module wheel speed PID match the PCM vehicle speed PID? 
    • Yes  : GO to A10.
    • No  : Refer to INTRODUCTION - GASOLINE article to diagnose the output shaft sensor (OSS) signal.
  10. A10 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 are seated 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 - GASOLINE ENGINES . CLEAR the DTCs. REPEAT the self-test.
    • No  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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