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Test DP: Vehicle Speed Sensor/Transfer Case Speed Sensor: Testing

NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION  table of fault code setting condition.
FAULT CODE SETTING CONDITION

Fault Code KOEO KOER Continuous Memory
P0500 1 3       DP30
P0500 2       DP1
P0501 3       DP1
P0503      DP20
P1500      DP20
P1501    DP15  
P1502 1       DP30
P1502 2       DP1
(1)
For pickup under 8500 GVW & 4WD Manual Shift-On-The-Fly.
(2)
For all Other vehicles.
(3)
For Excursion, Pickups 5.4L & 6.8L over 8500 GVW see FAULT CODE SETTING CONDITION .
    NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  1. 1) For Continuous Memory Only DTC P0500, P0501 & P1502: Check VSS Circuits For Open In Harness (VRS Type)
    DTCs P0500, P0501and P1502 indicate that PCM has detected an error in vehicle speed information received from Vehicle Speed Sensor (VSS), Transfer Case Speed Sensor (TCSS) or Anti-Lock Brake System (ABS) module. Possible causes for this fault are:
    • Open or short in VSS (+) or VSS (-) circuit.
    • Open in TCSS signal or TCSS signal return circuit.
    • Short to GND in VSS or TCSS circuit.
    • Short to PWR in VSS or TCSS circuit.
    • Open or short in VSC between PCM and appropriate control module.
    • Faulty wheel speed sensor(s).
    • Faulty wheel speed sensor(s) wiring harness.
    • Faulty module(s) connected to vehicle speed circuit.
    • Faulty transfer case, vehicle or wheel speed sensors.
    • Faulty drive mechanism for VSS or TCSS.

    Turn ignition switch to OFF position. Disconnect VSS connector. Disconnect PCM connector. Inspect connectors for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of VSS(+) and VSS (-) circuits between PCM harness connector and VSS harness connector. See Figure and Figure . If both resistance measurements are less than 5 ohms, go to next step. If either resistance measurement is 5 ohms or more, repair open in affected VSS(+) or (-) circuit. Perform DRIVE CYCLES . Ensure OBD-II DRIVE CYCLE is performed to verify repair.

  2. 2) Check VSS Circuits For Shorts To Ground Or Power In Harness

    Using a DVOM, measure resistance between VSS(+) circuit, and PWR GND, VPWR and VSS(-) circuits at PCM harness connector. See WIRING DIAGRAMS . See Figure and Figure . If all resistance measurements are more than 5 ohms, go to next step. If any resistance measurement is 5 ohms or less, go to step .

  3. 3) Check VSS Resistance

    Using a DVOM, measure resistance between VSS terminals. If resistance is not 170-270 ohms, replace VSS. If resistance is 170-270 ohms, replace PCM.
    4. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 4) to step 15). No test procedures have been omitted.

  4. 4) Verify If VSS Circuit Is Shorted In Harness Or Another Module
    Determine which, if any, modules are connected to the VSS circuit. See WIRING DIAGRAMS . If no other modules are connected to the VSS circuit, repair short circuit. Perform DRIVE CYCLES . Ensure OBD-II DRIVE CYCLE is performed to verify repair. If other modules are connected, one at a time, disconnect the modules associated with the VSS circuit. After disconnecting each module, again test for short circuit. Repeat until each associated module has been disconnected or the short circuit has been eliminated. If the short circuit remains after all associated modules were disconnected, repair short circuit in appropriate VSS circuit. Perform DRIVE CYCLES . Ensure OBD-II DRIVE CYCLE is performed to verify repair. If short is associated with a connected module, see appropriate diagnostic article for that module.
    5. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 15) to step 20). No test procedures have been omitted.

  5. 15) For KOER Only DTC P1501: Check PCM VSS PID For Input Signal
    This DTC indicates VSS input signal was detected by PCM during self-test. A DTC P1501 will be stored and self-test will abort when this occurs. Noisy VSS input signal from Radio Frequency Interference (RFI) or Electromagnetic Interference (EMI) external source (i.e.; ignition wires, charging circuits, etc.) can be possible causes for this fault.

    Connect scan tool to Data Link Connector (DLC). Start engine and allow to idle. Using scan tool, access VSS PID from PID/DATA MONITOR & RECORD menu and observe vehicle speed input to PCM. While observing VSS PID, increase engine speed to 2000 RPM and return to idle several times. If VSS PID reading is 3 MPH or more, go to step  22). If VSS PID value is less than 3 MPH, fault cannot be duplicated at this time. Clear DTCs and repeat QUICK TEST . If DTC P1501 is still present, go to TEST Z, step 1) .

    6. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  6. 20) For Continuous Memory Only DTC P0503 & P1500: Check For Intermittent Fault
    This DTC indicates poor or noisy VSS performance. Possible causes for this fault are:
    • Noisy TCSS/VSS Input Signal From Radio Frequency Interference (RFI) or Electromagnetic Interference (EMI) (Ignition Wires, Charging Circuits, Etc.)
    • Faulty VSS Or Driven Gears
    • Faulty TCSS
    • Damaged Wiring Harness Or Connectors
    • Faulty Module Or Circuit Connected To TCSS/VSS
    • Aftermarket Add-On Accessories

    Turn ignition switch to OFF position. Disconnect VSS sensor. Visually inspect VSS and VSS circuits for potential faults as follows:

    • Loose VSS Circuit Connectors
    • Loose VSS Circuit Connector Terminals
    • Damaged VSS Wiring Harness Insulation
    • Incorrect VSS Circuit Routing
    • Incorrect VSS Installation

    If no faults are found, go to next step. If faults are found, repair as necessary. Perform DRIVE CYCLES . Ensure OBD-II DRIVE CYCLE is performed to verify repair.

  7. 21) Check PCM VSS PID For Input Signal

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Using scan tool, access VSS PID from PID/DATA MONITOR & RECORD menu. Test drive vehicle at several steady speeds at more than, and less than 30 MPH.
    NOTE: On scan tools with Data Record feature, record data for playback to help identify variations.

    During each steady state speed, check for VSS PID variations of plus or minus 5 MPH for more than 10 seconds. If any variations occur, go to next step. If variations do not occur, fault cannot be duplicated at this time. Testing is complete.

  8. 22) Check VSS Harness Routing

    Visually inspect VSS wiring harness. Ensure wiring is not routed near high current wires such as ignition wires or charging system wires. Verify VSS wiring harness is shielded and grounded (if applicable). Check VSS wiring harness resistance. Refer to Figure-Fig 2 to check VSS circuits. If faults are found, repair as necessary. If no faults are found, fault cannot be duplicated at this time. Go to TEST Z, step 1) and check for intermittents.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 30). No test procedures have been omitted.
    9. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  9. 30) For Continuous Memory Only DTCs P0500 & P1502: Visual Inspection
    DTCs indicates the Powertrain Control Module (PCM) detected an error in the vehicle speed information. Vehicle speed data is received from either the Vehicle Speed Sensor (VSS), Transfer Case Speed Sensor (TCSS) or Anti-Lock Brake System (ABS) control module. If the engine RPM is above the torque converter stall speed (automatic transmission) and engine load is high, it can be inferred that the vehicle must be moving. If there is insufficient vehicle speed data input, a malfunction is indicated and a DTC is set. On most vehicle applications, the Malfunction Indicator Lamp (MIL) will be triggered when this DTC is set. Possible causes are:
    • Open in VSS+/VSS- harness circuit.
    • Open in TCSS signal or TCSS signal return harness circuit.
    • Short to GND in VSS harness circuit.
    • Short to GND in TCSS harness circuit.
    • Short to PWR in VSS harness circuit.
    • Short to PWR in TCSS harness circuit.
    • Open or short in the vehicle speed circuit(s) (VSC) between the PCM and appropriate control module.
    • Damaged VSS or TCSS.
    • Damaged wheel speed sensors.
    • Damaged wheel speed sensor harness circuits.
    • Damage in module(s) connected to VSC/VSS circuit.
    • Damage drive mechanism for VSS or TCSS.

    TCSS provides rotational speed of transfer case output shaft. PCM uses this signal to control powertrain behavior and on some models is used as source of vehicle speed information. Disconnect TCSS connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. If connector terminals are okay, go to next step.

  10. 31) Check Resistance Of TCSS

    Using a DVOM, measure resistance between TCSS SIG and TCSS SIG RTN circuits at TCSS connector. See Fig 1 or Fig 2 . If resistance is 1000-1250 ohms, go to next step. If resistance is not 1000-1250 ohms, replace TCSS.
    Fig 1: Identifying TCSS Circuits & Connector Terminals (Pickup 4.2L 4WD With Manual Shift-On-The-Fly)
    G99C02104Courtesy of FORD MOTOR CO.
    Fig 2: Identifying TCSS Circuits & Connector Terminals (Pickup 4.6/5.4L 4WD With Manual Shift-On-The-Fly)
    G00152738Courtesy of FORD MOTOR CO.

  11. 32) TCSS Output Check

    Road test vehicle and measure frequency between TCSS SIG and TCSS SIG RTN circuits at TCSS connector. Drive vehicle between zero and 30 MPH. Compare TCSS frequency to the frequency listed in appropriate PIN VOLTAGE/PID VALUE - INPUTS chart in appropriate PIN VOLTAGE/PID VALUE CHARTS article. Ensure frequency increases and decreases with vehicle speed. If frequency is as specified, go to next step. If frequency is not as specified, remove TCSS from transfer case. Inspect TCSS target wheel and repair as necessary. If TCSS target wheel is okay, replace TCSS.

  12. 33) Check Harness For Short To PWR

    Turn ignition switch to ON position. Disconnect TCSS connector. Using a DVOM, measure voltage between chassis ground and TCSS SIG circuit at TCSS harness connector. See Fig 1 or Fig 2 . If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to PWR.

  13. 34) Check Harness For Open

    Turn ignition switch to OFF position. Disconnect PCM connector. Using a DVOM, measure resistance of TCSS SIG and TCSS SIG RTN circuits between TCSS harness connector and PCM harness connector. See Fig 1 or Fig 2 . If both resistance measurements are less than 5 ohms, go to next step. If either resistance measurement is 5 ohms or more, repair open in affected circuit.

  14. 35) Check Harness For Short To Ground

    Using a DVOM, measure resistance between TCSS SIG circuit, TCSS SIG RTN circuit and chassis ground at TCSS harness connector. See Fig 1 or Fig 2 . If both resistance measurements are more than 10 k/ohms, replace PCM. If either resistance measurement is 10 k/ohms or less, repair short to ground in TCSS SIG circuit.
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