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International Automotive Technicians Network
Re: 1991 Caravan Speedo Code 15 from U-NO-Where
Posted to Technical Discussion Forum on 3/25/2004

You can't 'update' a VSS system to a TCM-generated VSS system via flashing the controller!! You might as well try to flash a 3-speed to being a 4-speed!

On a 91, the PCM (SMEC) looks for the VSS signal on the two wires that go to the physical VSS. The only w... Login to read more.