First off, I'll say I know little about trannies. I was reading through my service manual last night and the trans section said that there's a vacuum sensor that controls TCC lockup. Is this a MAP type vacuum sensor or just a solenoid (700-R4)? If it's a MAP type would some code changes allow a MAF car have a MAP? Just a crazy idea.

 

You aren't talking about a vacuum modulator used to sense engine load and control shift points, are you?

If there's a vacuum "sensor" in the tranny itself, it is surely a switch and not an electrical transducer like the MAP sensor.

I guess I can't see why there would have to be a vacuum break in the TCC circuit, as it is controlled by the ECM anyway, which has full knowledge of the manifold vacuum!

 

Chiilton, or Haynes?.
Whichever, it's dead wrong, as far as efi cars. They use % TPS and vehicle speed sensor(and gear / brake switches) (with a coolant temp enable).

 

The "sensor" you are talking about is not a sensor. There is a combo TCC power switch / Cruise Control vacuum release switch that activates when you push on your brake pedal. This interrupts the power to the TCC solenoid, and "turns it off" while braking, and also releases the vacuum that keeps your cruise control "on". As soon as the brakes are released, the power to the purple wire (solenoid positive) is restored.

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Mike Metzler (Desert86Roc)[*] Check Out:SpeedWorldMotorplex.com[*] Check Out:Chevrolet F-Body Online Part & Illustration Manual[*] My 86 IROC 305 TPI Page (406 build in progress)

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