LEMON Manuals: Even more car manuals for everyone
Home >> Mercury >> 2008 >> Milan Base, 3.0 1, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1908 (Engine Controls - Pinpoint Test DK: Accelerator Pedal Position Sensor Through Pinpoint Test DX: Engine Coolant Temperature (ECT) Sensor - (Except Diesel & Hybrid)) >> Pinpoint Test DP: Vehicle Speed Sensor (VSS)/Transfer Case Speed Sensor (TCSS) >> Test Procedure

Test Procedure

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
  1. DP1 DTCS P0500, P0501 AND P1502: VERIFY DRIVE CYCLE 
    • Access the PCM and monitor the VSS PID.
    • Drive the vehicle.
    • Monitor the PID in all transmission gear ranges while increasing and decreasing the speed.

    Does the PID reading increase and decrease with engine and vehicle speed? 

    Yes No
    VSS performed as expected.
    GO to  DP2.    		 Key in OFF position.
    GO to  DP3.
  2. DP2 VISUAL INSPECTION 
    • VSS connector disconnected.
    • Inspect the VSS harness for damage.
    • Inspect the VSS vehicle harness connector for damage and proper seating.
    • If possible, carry out a wiggle test.

    Is a concern present? 

    Yes No
    REPAIR as necessary GO to PINPOINT TEST Z STEP 1 .
  3. DP3 VERIFY THE TYPE OF VSS SENSOR 
    NOTE: VR (variable reluctance) sensors have 2-wire connectors, Hall-effect sensors have 3-wire connectors.
    • Inspect for a Hall-effect or a VR type of VSS sensor.

    Is this a Hall-effect type VSS sensor? 

    Yes No
    GO to  DP4. GO to  DP6.
  4. DP4 CHECK VPWR TO THE VSS SENSOR 
    • VSS connector disconnected.
    • Key in ON position.
    • Measure the voltage between:
      (+) VSS Connector, Harness Side (-) Vehicle Battery
      VPWR Negative terminal

    Is the voltage greater than 10.5 V? 

    Yes No
    Key in OFF position.
    GO to  DP5.    		 Key in OFF position. REPAIR the open circuit.
  5. DP5 CHECK THE VPWR GROUND TO THE VSS SENSOR 
    • Measure the resistance between:
      (+) VSS Connector, Harness Side (-) Vehicle Battery
      PWRGND Negative terminal

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  DP6. REPAIR the open circuit.
  6. DP6 CHECK THE VSS CIRCUIT FOR A SHORT TO VREF AND VPWR IN THE HARNESS 
    • Key in ON position.
    • VSS connector disconnected.
    • Measure the voltage between:
      (+) VSS Connector, Harness Side (-) Vehicle Battery
      VSS Negative terminal

    Is the voltage less than 1 V? 

    Yes No
    Key in OFF position.
    GO to  DP7.    		 Key in OFF position. REPAIR the short circuit.
  7. DP7 CHECK THE VSS CIRCUIT(S) FOR AN OPEN IN THE HARNESS 
    • PCM connector disconnected.
    • VSS connector disconnected.
      NOTE: Hall-effect sensors are not equipped with a SIGRTN circuit. Disregard SIGRTN measurement.
    • Measure the resistance between:
      (+) PCM Connector, Harness Side (-) VSS Connector, Harness Side
      VSS VSS
      SIGRTN PWRGND

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  DP8. REPAIR the open circuit.
  8. DP8 CHECK THE VSS CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS 
    • Measure the resistance between:
      (+) VSS Connector, Harness Side (-) VSS Connector, Harness Side
      VSS PWRGND
      VSS VSS-GND
    • Measure the resistance between:
      (+) VSS Connector, Harness Side (-)
      VSS Ground

    Are the resistances greater than 10, 000 Ohms? 

    Yes No
    For Hall Effect
    GO to  DP9.
    For VR (Variable Reluctance)
    GO to  DP10.    		 REPAIR the short circuit.
  9. DP9 CHECK THE VSS SIGNAL OUTPUT TO THE PCM, HALL-EFFECT TYPE SENSOR 
    • PCM connector disconnected.
    • Raise the vehicle to allow for the rotation of the front drive wheels.
    • Key in ON position.
    • Transmission in NEUTRAL.
    • Measure the voltage between:
      (+) PCM Connector, Harness Side (-) PCM Connector, Harness Side
      VSS PWRGND
      • NOTE: The opposite wheel must be held stationary.
    • The voltage should rise above 5 volts and fall below 1 volt in a regular cycle. Observe several cycles.

    Does the VSS output voltage rise and fall as specified? 

    Yes No
    INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . REMOVE the VSS sensor and inspect the target wheel.
    REPAIR as necessary.
    If OK, INSTALL a new VSS sensor.
  10. DP10 CHECK THE RESISTANCE OF THE VSS SENSOR 
    • Measure the resistance between:
      (+) VSS Connector, Component Side (-) VSS Connector, Component Side
      VSS VSS-GND

    Is the resistance between 170 ohms - 270 ohms? 

    Yes No
    INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . REMOVE the VSS sensor and inspect the target wheel.
    REPAIR as necessary.
    If OK, INSTALL a new VSS sensor.
  11. DP11 KOER DTC P1501: CHECK THE VSS PID FOR AN INPUT SIGNAL 
    • Key on engine running.
    • Access the PCM and monitor the VSS PID.
    • Observe the VSS input to the PCM.
    • Increase the engine speed, not greater than 2, 000 RPM, several times while observing the VSS PID.

    Is the reading on the PID less than 5 km/h (3 mph)? 

    Yes No
    Unable to duplicate or identify the fault at this time.
    REFER to POWERTRAIN DTC CHARTS AND DESCRIPTIONS - GASOLINE MODELS for possible causes and additional DTC description information.
    If DTC P1501 still exists
    GO to PINPOINT TEST Z STEP 1 .    		 GO to  DP14.
  12. DP12 DTCS P0503 AND P1500: INSPECT THE VSS AND THE CIRCUIT FOR AN INTERMITTENT 
    • Visually inspect the VSS and harness circuits for any potential failures.
    • Use the following check list for reference:
      • Loose wires/connectors.
      • Pushed out connector pins.
      • Damaged wiring harness insulation.
      • Incorrect harness routing.
      • Incorrect VSS mounting.

    Is a concern present? 

    Yes No
    REPAIR as necessary. GO to  DP13.
  13. DP13 CHECK THE PCM VSS PID FOR AN INPUT SIGNAL 
    • Access the PCM and monitor the VSS PID.
    • Drive the vehicle at several steady state speeds above and below 50 km/h (30 mph).
      • NOTE: For diagnostic tools which have a data record feature, record the data for future playback to help identify any variations.
    • During each steady state speed observe the VSS PID for variations of (+) or (-) 8 km/h (5 mph) for greater than 10 seconds.

    Are there any indicators of a noisy or intermittent signal with the VSS PID? 

    Yes No
    GO to  DP14. Unable to duplicate or identify the fault at this time. REPAIR any other DTCs.
    Concern is elsewhere. RETURN to SYMPTOM CHARTS - GASOLINE MODELS for further direction.
  14. DP14 CHECK THE VSS HARNESS ROUTING 
    • Check the VSS harness routing.
    • Verify the harness is not routed adjacent to any high current wires such as ignition wires or generator wiring.
    • Verify the VSS harness is shielded and grounded, if applicable.
    • Measure the resistance of the VSS harness.
    • Refer to Connectors views at the beginning of this pinpoint test.

    Is a concern present? 

    Yes No
    REPAIR as necessary. Unable to duplicate or identify the fault at this time.
    REFER to POWERTRAIN DTC CHARTS AND DESCRIPTIONS - GASOLINE MODELS for possible causes and additional DTC description information.
    GO to PINPOINT TEST Z STEP 1 .
  15. DP15 DTCS P0500 AND P1502: VISUAL INSPECTION OF TCSS 
      NOTE: The TCSS provides the rotational speed of the output shaft of the transfer case.
      • The PCM uses this information to control the powertrain behavior and on some applications it is used as the source for the vehicle speed information.
    • TCSS connector disconnected.
    • Inspect the TCSS vehicle harness connector for damage and proper seating.

    Is a concern present? 

    Yes No
    REPAIR as necessary. GO to  DP16.
  16. DP16 CHECK THE RESISTANCE OF THE TCSS 
    • Measure the resistance between:
      (+) TCSS Connector, Component Side (-) TCSS Connector, Component Side
      SIGRTN - Pin 1 TCSS - Pin 2

    Is the resistance between 1K ohms - 1.25K ohms? 

    Yes No
    GO to  DP17. INSTALL a new TCSS.
  17. DP17 CHECK THE TCSS SENSOR OUTPUT 
    • Raise the vehicle. REFER to JACKING AND LIFTING for the proper way to lift the vehicle. Put the vehicle in NEUTRAL with the parking brake off. Take safety precautions as necessary.
    • Measure the frequency between:
      (+) TCSS Connector, Component Side (-) TCSS Connector, Component Side
      SIGRTN - Pin 1 TCSS - Pin 2
    • Monitor the TCSS signal while rotating the driven wheel as fast as possible.
      NOTE: The opposite wheel must be held stationary.
    • Refer to TYPICAL DIAGNOSTIC REFERENCE VALUES .

    Does the frequency reading increase and decrease with the wheel speed? 

    Yes No
    GO to  DP18. REMOVE the TCSS and inspect the target wheel.
    REPAIR as necessary.
    If OK, INSTALL a new TCSS sensor.
  18. DP18 CHECK THE TCSS CIRCUIT(S) FOR A SHORT TO GROUND AND POWER IN THE HARNESS 
    • Key in ON position.
    • TCSS connector disconnected.
    • Measure the voltage between:
      (+) TCSS Connector, Harness Side (-)
      TCSS - Pin 2 Ground

    Is the voltage less than 1 V? 

    Yes No
    Key in OFF position.
    GO to  DP19.    		 Key in OFF position. REPAIR the short circuit.
  19. DP19 CHECK THE CIRCUIT(S) FOR AN OPEN IN THE HARNESS 
    • PCM connector disconnected.
    • Measure the resistance between:
      (+) PCM Connector, Harness Side (-) TCSS Connector, Harness Side
      TCSS TCSS - Pin 2
      SIGRTN SIGRTN - Pin 1

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  DP20. REPAIR the open circuit.
  20. DP20 CHECK THE HARNESS FOR A SHORT TO GROUND 
    • Measure the resistance between:
      (+) TCSS Connector, Harness Side (-) TCSS Connector, Harness Side
      SIGRTN - Pin 1 TCSS - Pin 2
    • Measure the resistance between:
      (+) TCSS Connector, Harness Side (-)
      TCSS - Pin 2 Ground

    Are all the resistances greater than 10, 000 ohms? 

    Yes No
    INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . REPAIR the short circuit.
scientia non olet · About LEMON Manuals