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Tim's Auto Repair
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i am having vehicle speed sensor problems on my 2000 silverado

Resolved Question:

i am having vehicle speed sensor problems on my 2000 silverado 4.8 with 4l60e transmission. i have put new vss,reluctor ring,brake pump & module,wheel bearings,abs wheel speed sensors, and a new wire from pcm to vss. fault code says vss low voltage still, speedometer jumps up and down and it makes my tranny shift crazy. i have found the wires coming from pcm that my book says but it says they are dark geen and white but there are six of them and i dont know how to test them
Submitted: 8 years ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 8 years ago.

what is the code # XXXXX are getting...i will send you a chart on how to fix this problem


Customer: replied 8 years ago.


Expert:  Tim's Auto Repair replied 8 years ago.


this should help you fix his problem


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4L60-E / 4L65-E Automatic Transmission


Diagnostic Chart (Part 1 Of 2)
Diagnostic Chart (Part 2 Of 2)
The Vehicle Speed Sensor (VSS) assembly provides vehicle speed information to the Powertrain Control Module (PCM) . The VSS assembly is a Permanent Magnet (PM) generator. The PM generator produces a pulsing AC voltage as rotor teeth on the output shaft of the transmission (2WD) or transfer case (4WD) pass through the sensor's magnetic field. The AC voltage level and the number of pulses increase as the speed of the vehicle increases. The PCM converts the pulsing voltage to vehicle speed. The PCM uses the vehicle speed signal to determine shift timing and Torque Converter Clutch (TCC) scheduling.

When the PCM detects a low vehicle speed when there is a high engine speed in a drive gear range, then DTC P0502 sets. DTC P0502 is a type B DTC.



  • No MAF sensor DTCs P0101, P0102 or P0103.
  • No MAP sensor DTCs P0107 or P0108.
  • No TP sensor DTCs P0122 or P0123.
  • No TFP manual valve position switch DTC P1810.
  • The engine vacuum is 0-105 kPa .
  • The engine torque is 40-400 ft lb .
  • The TP angle is greater than 20% .
  • The engine speed is greater than 3000 RPM .
  • The transmission is not in PARK or NEUTRAL.

The transmission output speed is less than 150 RPM for 2.5 seconds .


  • The PCM illuminates the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
  • The PCM commands second gear only.
  • The PCMcommands maximum line pressure.
  • The PCM inhibits TCC engagement.
  • The PCM freezes shift adapts from being updated.
  • The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
  • The PCM stores DTC P0502 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.


  • The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
  • A scan tool can clear the MIL/DTC.
  • The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
  • The PCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM.


  • Inspect the connectors at the PCM the VSS assembly and all other circuit connecting points for an intermittent condition. Refer to Testing for intermittent and Poor Connections in Diagrams.
  • Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents in Diagrams.

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests the VSS assembly circuit.
  2. This step tests the integrity of the VSS assembly.
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