Diagnostic Aids

Code 72 will set when VSS signal is present and is lost. Code 24 will set when no vehicle speed is detected at vehicle start off. Check all connections, especially those at transmission pass-through connector. If code is intermittent, see INTERMITTENTS in TESTS W/O CODES - GASOLINE article.

Fig 1: Code 72 Schematic ("C", "G", "K", "L", "M" & "P" Series) VSS Circuit Loss Transmission Output Signal

Fig 2: Code 72 Schematic ("S" & "T" Series) VSS Circuit Loss Transmission Output Signal

Fig 3: Code 72 Flow Chart (All Models) VSS Circuit Loss Transmission Output Signal