Toyota Altezza VSS Vehicle Speed Sensor wiring help needed.

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Hi there. We have wired the Toyota Altezza 3sge beams VSS Vehicle Speed Sensor on the gearbox with 5v from the Link Ecu, Ground from the ECU and returned the signal wire to DI 3 LR Wheel speed. I am now fitting a Toyota Speedometer head to the car. This means I need on the three terminals on the speedometer head IG+ which is 12v via key on, ground via batt earth and signal via the VSS on the gearbox. The question I have is that in a Toyota the VSS is fed with 12v not 5v from the Ecu. Will this matter. I am concerned that the 5v coming from the VSS will not be enough to run the speedo head. Can i put 12v onto the VSS and disconnect the 5v coming from the ecu to the VSS. This will mean the VSS will return a 12v signal to the DI 3. Will this do hard and damage the Ecu? Or is there a better way to do this? Thanks Rex

 

[Vaughan]

12V will not damage the DI inputs. I'm not super familiar with the Altezza speedo drive but I suspect the link setup needs the 5V on the drive to work properly and that it might not pick up the signal if the speed sensor is hooked up to 12V (will be to do with the voltage that it has to cross to be considered a state change). What you could do is keep the speed sensor fed into the Link and then use an Aux output from the link to control the dash speedo.

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Is there a way with the speedo output to make a ratio/correction change to correct speedo speed error. Thanks for your help.

[Vaughan]

there is indeed, I've used speed into ECU then speed out of ECU into dash to correct the speedo on two of my cars