Your Vehicle: 2001 Ford Escort ZX2 L4-2.0L DOHC VIN 3
 
Vehicle » Powertrain Management » Computers and Control Systems » Testing and Inspection » Pinpoint Tests » DP: Vehicle Speed Sensor (VSS)/Transfer Case Speed Sensor (TCSS) - Pinpoint Test  
 
 
  DP: Vehicle Speed Sensor (VSS)/Transfer Case Speed Sensor (TCSS) - Pinpoint Test  
 

DP: Vehicle Speed Sensor (VSS)/Transfer Case Speed Sensor (TCSS)

DP: Introduction See: DP: Vehicle Speed Sensor (VSS)/Transfer Case Speed Sensor (TCSS) - Introduction

DP1 DTC P0500/P0501/P1502: CHECK VSS CIRCUITS FOR OPEN IN HARNESS (VRS TYPE)

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

  • Disconnect PCM.
  • Disconnect VSS.
  • Measure resistance of VSS+ circuit between PCM harness connector pin and VSS+ sensor harness connector.
  • Measure resistance of VSS- circuit between PCM harness connector pin and VSS- sensor harness connector.

Is each resistance less than 5.0 ohms?
Yes

  • GO to DP2

.

No

  • REPAIR open circuit. COMPLETE an OBD II Drive Cycle (REFER to

Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

DP2 CHECK VSS CIRCUITS FOR SHORT TO GROUND AND POWER IN HARNESS

  • Measure resistance between VSS+ and PWR GND circuits at PCM harness connector.
  • Measure resistance between VSS+ and VSS- circuits at PCM harness connector.
  • Measure resistance between VSS+ and VPWR circuits at PCM harness connector.

Is each resistance greater than 5.0 ohms?
Yes

  • GO to DP3

.

No

  • GO to DP12

.

DP3 CHECK VSS RESISTANCE

  • Measure VSS resistance.

Is resistance between 170 and 270 ohms?
Yes

).
COMPLETE an OBD II Drive Cycle (REFER to Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles
).

No

  • REPLACE the VSS. COMPLETE an OBD II Drive Cycle (REFER to

Section 2 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods
, Drive Cycles).

DP5 DTC P0500/P0501/P1502: CHECK VSS SIGNAL OUTPUT TO (PCM) POWERTRAIN CONTROL MODULE (HALL TYPE)

  • Disconnect PCM.
  • Raise the vehicle to allow rotation of the front drive wheel.
  • Key on, transmission in NEUTRAL.

Note: The opposite wheel must be held stationary.

  • Measure voltage between VSS+ and PWR GND circuits at the PCM harness connector, while slowly rotating the drive wheel.
  • The voltage should rise above 5.0 volts and fall below 1.0 volt in a regular cycle. Observe several cycles.
  • Key off.

Does the VSS output voltage rise and fall as specified while slowly rotating the drive wheel?
Yes

COMPLETE an OBD II Drive Cycle (REFER to Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles
).

No

  • GO to DP6

.

DP6 CHECK VOLTAGE BETWEEN VPWR AND PWR GND CIRCUITS AT VSS

  • Disconnect VSS.
  • Key on.
  • Measure voltage between VPWR and PWR GND circuits at the VSS harness connector.

Is the voltage greater than 10.5 volts?
Yes

  • GO to DP7

.

No

  • KEY OFF. GO to DP10

.

DP7 CHECK VSS CIRCUIT FOR SHORT TO POWER IN HARNESS

  • Key on.
  • Measure voltage between VSS+ and PWR GND circuits at the PCM harness connector.
  • Key off.

Is voltage less than 1.0 volt?
Yes

  • GO to DP8

.

No

  • GO to DP12

.

DP8 CHECK VSS CIRCUIT FOR SHORT TO GROUND IN HARNESS

  • Measure resistance between VSS+ and PWR GND circuits at the PCM harness connector.

Is resistance greater than 3,000 ohms?
Yes

  • GO to DP9

.

No

  • GO to DP12

.

DP9 CHECK VSS SIGNAL CIRCUIT FOR OPEN IN HARNESS

  • Measure resistance of VSS+ signal circuit between PCM harness connector pin and VSS+ sensor harness connector.

Is resistance less than 5.0 ohms?
Yes

  • REPLACE VSS. COMPLETE an OBD II Drive Cycle (REFER to Section

2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

No

  • REPAIR open circuit. COMPLETE an OBD II Drive Cycle (REFER to

Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

DP10 CHECK VSS GROUND CIRCUIT FOR OPEN IN HARNESS

  • Measure resistance of PWR GND circuit between VSS harness connector and chassis ground.

Is resistance less than 5.0 ohms?
Yes

  • REPAIR open VPWR to VSS. COMPLETE an OBD II Drive Cycle (REFER

to Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

No

  • REPAIR open VSS PWR GND circuit. COMPLETE an OBD II Drive Cycle

(REFER to Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

DP12 VERIFY IF VSS CIRCUIT IS SHORTED IN HARNESS OR ANOTHER MODULE

  • Determine which, if any, modules are connected to the VSS circuit (Refer to Wiring Diagrams). If no other modules are connected to the VSS circuit, GO to the "YES" Action To Take.
  • One at a time, disconnect the modules associated with the VSS circuit. After disconnecting each module, again test for short circuit (Refer to test step that sent you here). Repeat until each associated module has been disconnected or the short circuit has been eliminated.

Does the short circuit remain after all associated modules were disconnected?
Yes

  • REPAIR short circuit. COMPLETE an OBD II Drive Cycle (REFER

to Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

No

  • REFER to the diagnostic/repair information for further diagnosis of appropriate

module.

DP15 KOER DTC P1501: CHECK PCM VSS PID FOR INPUT SIGNAL

  • Start the engine and idle in NEUTRAL.
  • Access the VSS PID with a scan tool and observe for vehicle speed input to the PCM.
  • Increase the engine speed, not greater than 2000 rpm, several times while observing the VSS PID.

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

  • Unable to duplicate or identify fault at this time. If DTC P1501

still exists. GO to Z1 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 5: Pinpoint Tests\Z: Intermittent - Pinpoint Test

  1. (REFER to Section 4, Diagnostic Trouble Code (DTC) Descriptions See: A L L Diagnostic Trouble Codes ( DTC )\Testing and Inspection\Diagnostic Trouble Code Descriptions for a list of possible

causes.)

No

  • GO to DP22

.

DP20 DTC P0503: INSPECT VSS AND CIRCUIT FOR AN INTERMITTENT

  • Check for harness intermittents by verifying that Pins are properly seated in connector shell, wiring is properly crimped, no corrosion exists in the harness and sensor is securely mounted.

Are there any indications of harness intermittents?
Yes

  • REPAIR as necessary. COMPLETE an OBDII Drive Cycle (REFER to

Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

No

  • GO to DP21

.

DP21 CHECK PCM VSS PID FOR INPUT SIGNAL

  • Access the VSS PID with a scan tool.
  • Drive the vehicle at several steady state speeds above and below 50 km/h (30 mph).

Note: For Scan Tools which have Data Record feature, record data for playback to help identify variations.

  • During each steady state speed observe the VSS PID for variations of (+) or (-) 8 km/h (5 mph) for greater than 10 seconds.

Is there any indications of a noisy or intermittent signal with the VSS PID?
Yes

  • GO to DP22

.

No

  • Unable to duplicate or identify fault at this time. REPAIR any

other DTCs.

DP22 CHECK VSS HARNESS ROUTING

  • Check VSS harness routing:
  • Verify that the harness is not routed adjacent to high current wires such as ignition wires or generator wiring.
  • Verify VSS harness is shielded and grounded, if applicable.
  • Check resistance of the VSS harness; refer to Pinpoint Test Schematic and Connectors at beginning of pinpoint test.

Are any concerns evident?
Yes

  • REPAIR as necessary. COMPLETE an OBDII Drive Cycle (REFER to

Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

No

  1. (REFER to Section 4, Diagnostic Trouble Code (DTC) Descriptions See: A L L Diagnostic Trouble Codes ( DTC )\Testing and Inspection\Diagnostic Trouble Code Descriptions for a list of possible causes.)

DP25 DTC P1500: VISUAL INSPECTION

  • Visually inspect the VSS and VSS harness circuits for any potential failures. Use the following check list for reference:
  • Loose VSS connector.
  • Pushed out VSS connector pins.
  • Damaged VSS wiring harness insulation.
  • Incorrect harness routing.
  • Incorrect VSS mounting.

Did the visual inspection reveal a potential failure?
Yes

  • REPAIR fault as necessary. COMPLETE an OBD II Drive Cycle (REFER

to Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

No

  • RESTORE vehicle. Unable to duplicate or identify fault at this

time. GO to Z1 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 5: Pinpoint Tests\Z: Intermittent - Pinpoint Test

  1. (REFER to Section 4, Diagnostic Trouble Code (DTC) Descriptions See: A L L Diagnostic Trouble Codes ( DTC )\Testing and Inspection\Diagnostic Trouble Code Descriptions for a list of possible causes.)

DP30 DTC P0500, P1502 VISUAL INSPECTION

Note: The transfer case speed sensor (TCSS) provides rotational speed of output shaft of the transfer case. The PCM use this information to control powertrain behavior and on some applications is used as the source of vehicle speed information.

  • Disconnect TCSS sensor.
  • Inspect TCSS vehicle harness connector for damage and proper seating.

Have any problems been found?
Yes

  • REPAIR as necessary.

No

  • GO to DP31

.

DP31 CHECK RESISTANCE OF TCSS SENSOR

  • Measure resistance between TCSS signal and TCSS SIGTRN circuits at the TCSS sensor.

Is resistance between 1,000 and 1,250 ohms?
Yes

  • GO to DP32

.

No

  • REPLACE TCSS sensor.

DP32 TCSS OUTPUT CHECK

Does frequency reading increase and decrease with vehicle speed?
Yes

  • GO to DP33

.

No

  • REMOVE the TCSS and inspect target wheel. REPAIR as necessary.

IF OK REPLACE TCSS.

DP33 CHECK HARNESS FOR SHORT TO PWR

  • Key on.
  • TCSS sensor disconnected.
  • Measure voltage between the TCSS signal circuit at the TCSS harness connector and ground.

If voltage less than 1.0 volt?
Yes

  • KEY OFF. GO to DP34

.

No

  • REPAIR short circuit.

DP34 CHECK HARNESS FOR OPEN

  • Disconnect PCM.
  • Measure resistance of TCSS signal circuit between PCM harness connector pin and TCSS sensor harness connector.
  • Measure resistance of TCSS SIGRTN circuit between PCM harness connector pin and TCSS sensor harness connector.

Is each resistance less than 5.0 ohms?
Yes

  • GO to DP35

.

No

  • REPAIR open circuit.

DP35 CHECK HARNESS FOR SHORT TO GROUND

  • Measure resistance between TCSS signal and SIGRTN circuits at the TCSS harness connector.
  • Measure resistance between TCSS signal and GND circuits at the TCSS harness connector.

Is each resistance greater than 10,000 ohms?
Yes

No

  • REPAIR short circuit.