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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Diagnosis - A/T >> Diagnostic Flow Charts (Cars) >> Code 24, Vehicle Speed Sensor (VSS) 5.0L & 5.7L TBI B, D & F Bodies >> Notes

Code 24, Vehicle Speed Sensor (VSS) 5.0L & 5.7L TBI B, D & F Bodies: Notes

Fig 1: Code 24, VSS Circuit Diagram 1 Of 4 (5.0L & 5.7L TBI B, D & F Bodies)
G91H07397Courtesy of GENERAL MOTORS CORP.
Fig 2: Code 24, VSS Circuit Diagram 2 Of 4 (5.0L & 5.7L TBI B, D & F Bodies)
G91J07398Courtesy of GENERAL MOTORS CORP.
Fig 3: Code 24, VSS Circuit Diagram 3 Of 4 (5.0L & 5.7L TBI B, D & F Bodies)
G92C04301Courtesy of GENERAL MOTORS CORP.
Fig 4: Code 24, VSS Circuit Diagram 4 Of 4 (5.0L & 5.7L TBI B, D & F Bodies)
G91B07399Courtesy of GENERAL MOTORS CORP.
NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. Code 24 will set if VSS signal circuit voltage is constant, engine speed is 1200-4400 RPM. TPS indicates throttle is near idle position, transmission is not in Park or Neutral and all conditions have been met for at least 4 seconds.
  2. A voltage of less than one volt at the instrument panel connector indicates that VSS signal circuit wire may be shorted to ground. Disconnect signal wire at the VSS buffer. If voltage remains less than 10 volts, circuit is shorted to ground or open. If circuit is not open or shorted to ground, check for poor control module connection or faulty control module.