What does the VSS reading tell the PCM?
Do I need a VSS if I'm running 2001 6.0 with a 700R4 behind it? Going in a tube buggy that will be trailered everywhere. Does it control the electronic throttle or anything important, or is it just used for an instrument cluster signal?
Thread Starter
Teching In
Joined: Apr 2009
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Do a search for VSS on this forum and others. It's a debated issue.
A lot of folks running manual or non electronic transmissions don't hook it up. Then again, a lot of those folks post about minor idle problems, stalling or surging on deceleration and other odd issues.
It would be interesting to try driving with it connected and disconnected to see if it makes a difference.
Hopefully someone who knows what they are talking about will chime in with better info.
A lot of folks running manual or non electronic transmissions don't hook it up. Then again, a lot of those folks post about minor idle problems, stalling or surging on deceleration and other odd issues.
It would be interesting to try driving with it connected and disconnected to see if it makes a difference.
Hopefully someone who knows what they are talking about will chime in with better info.
Two items regarding earlier posts...
- The "high priced" AA VSS kit includes the sensor housing/adapter and the reluctor ring that sits on the 4L60e output shaft. There is a lot more to it then the sensor.
- The T/C low range switch is there for those who want a low range indicator lamp input. (Nothing to do with the PCM)
Thread Starter
Teching In
Joined: Apr 2009
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Then how does the PCM know when to correct for the final drive ratio change in 4low and make corrections for the speedometer and proper gear shift changes in an OEM configuration?
It doesn't. The ECM is simply reading the VSS output.
The speedo will tell you you're flying, but...
...use the "manu-matic" mode to control gear selection. (As you're in creeper/crawler mode, that shouldn't be too big a deal.)
The speedo will tell you you're flying, but...
...use the "manu-matic" mode to control gear selection. (As you're in creeper/crawler mode, that shouldn't be too big a deal.)
