Holding a vac does not verify the delay actuating element or cable
mechanism as good. It simply means it does not leak...it does not mean it works.
The test is to couple the input/output lines at the Switch Over Valve [ not a solinoid relay]...then drive the car to see if the cable fulcrum holds the trans in delay gear. That test eliminates the electronic diagnosis b/c you are manually using the actuating mechanism via direct engine vac supply.

And if the BB trick is used , one only has to use the lower shift range when cold/first start to eliminate the CE lamp b/c it will not be called for by the ECU parameters b/c the rpm signal to set the 26 code fault will not be met.

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A Dalton