Abs light on speedometer ouit and wont shift - 1995 Chevrolet G20

Hi, I recommend you test or just replace your speed sensor. Instructions for testing are pasted below. The sensor is mounted on the side of the transmission with a single bolt and has a connector with 2 wires on it. It looks like the picture below, and costs about $35. When reinstalling, be sure to lubricate the o-ring with oil and twist while pushing in. Please let me know if you have questions and thanks for using FixYa.


A defective vehicle speed sensor may cause different problems depending on the computer output control functions. A defective vehicle speed sensor (VSS) may cause improper converter clutch lockup, improper cruise control operation, and inaccurate speedometer operation.

• Prior to VSS diagnosis, the vehicle should be lifted on a hoist so the drive wheels are free to rotate.
• Backprobe the vss output wire and connect the voltmeter leads from this wire to ground.
• Select the 20-volt AC scale on the voltmeter.
• Then start the engine.
• Place the transaxle in drive and allow the drive wheels to rotate. If the VSS voltage signal is not 0.5 volt, or more, replace the sensor.
• When the VSS provides the specified voltage signal, backprobe the VSS terminal at the PCM and repeat the voltage signal test with the drive wheels rotating.
• If 0.5 volt is available at this terminal, the trouble may be in the PCM (powertrain control module).
• When 0.5 volt is not available at this terminal, turn the ignition switch off and disconnect the wire from the VSS to the PCM.
• Connect the ohmmeter leads across the wire. the meter should read zero ohm.
• Repeat the test with the ohmmeter leads connected to the VSS ground terminal and the PCM ground terminal.
• This wire should also have zero ohm resistance. If the resistance in these wires is more than specified, repair the wires.
• The condition of a speed sensor can be checked by going through the diagnostic routines for the system.
• If this test indicates that a sensor is faulty, the sensor should be replaced.
• Speed sensors can also be checked with an ohmmeter. Most manufacturers list a resistance specification.
• The resistance of the sensor is measured across the sensor's terminals.
• The typical range for a good sensor is 800 to 1400 ohms of resistance.