Vehicle Speed Sensor (VSS)
With ignition on, backprobe VSS connector and ensure 12 volts is present at Red/White/Black wire (circuit No. 439). Ensure continuity exists between Black/White wire (ground circuit No. 450) and chassis ground. Using a DVOM, monitor voltage on Brown wire (circuit No. 437) while turning drive wheels. As Hall switch pulses circuit to ground, voltage should be pulled down. See Fig 1 . If a "Scan" tester is used to diagnose this component, see Code 24 diagnostic flow chart in SELF-DIAGNOSTICS article in this section.