Vehicle Speed Sensor: What does it do?

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oscarloco
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Vehicle Speed Sensor: What does it do?

Post by oscarloco »

Hi guys

After repairing the speedo drive a few weeks ago, I started wondering, what is the Vehicle Speed Sensor function?

I know it has something to do with the ignition, but what? :?:
Oscar Lopez
'94 ZX 2.0 8v petrol (restoration to its former glory on its way after being neglected by stupid Ex)
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Post by CitroJim »

Hi Oscar,

Depending on the model, it does several things:

It sends a speed signal to the Hydractive Computer to assist with hard/soft mode change decision process;

In manual gearbox cars it tells the Engine Management to maintain a slightly higher idle between gear changes to ensure a smooth change whilst the car is in motion;

In automatics it assists the gearbox ECU to make gearchange decisions;

It drives the speedo and odometer.

I'm sure it does more than that too but my mind has gone blank!
Jim

Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
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