# 12v vehicle speed sensor connection

**URL:** <https://community.ecumaster.com/t/12v-vehicle-speed-sensor-connection/3338>\
**Category:** GENERAL\
**Tags:** how-to\
**Created:** [March 11, 2025, 7:57pm UTC](https://community.ecumaster.com/t/12v-vehicle-speed-sensor-connection/3338 "2025-03-11T19:57:23Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![seant](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@seant](https://community.ecumaster.com/u/seant)\
**Post date:** [March 11, 2025, 7:57pm UTC](https://community.ecumaster.com/t/12v-vehicle-speed-sensor-connection/3338/1 "2025-03-11T19:57:23Z")

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Hi, Wiring up a hall effect vss to my emu black, installation manual shows it as a 5v feed / sensor ground and vss signal wire. Question? when using a 12v sensor is it wired. 12v ignition feed / power ground and then ok to use the vss input or do i use an aux input? Thanks

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**Author:** ![FloorItGarage](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/flooritgarage/32/61_2.png) [@FloorItGarage](https://community.ecumaster.com/u/FloorItGarage)\
**Post date:** [March 14, 2025, 9:04pm UTC](https://community.ecumaster.com/t/12v-vehicle-speed-sensor-connection/3338/2 "2025-03-14T21:04:47Z")

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You need to use the VSS input, an analog input doesn’t read pulses like the ones generated by a speed sensor.

Not sure what vehicle we’re discussing here but all the 12V VSS i’ve done output a low side (to ground) pulse and are totally fine connected to the VSS input pin.  
Some sensors are happy on 5-12V input, some are only happy at 5, others 12.

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**Author:** ![seant](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@seant](https://community.ecumaster.com/u/seant)\
**Post date:** [March 15, 2025, 8:46pm UTC](https://community.ecumaster.com/t/12v-vehicle-speed-sensor-connection/3338/3 "2025-03-15T20:46:25Z")

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Thankyou, Im using the vss input, but my vss is 12v only. its a sierra cosworth yb turbo in a mk1 escort. So was concerned about the voltage back up the vss input if i use 12v sensor. Should i use the power ground as the earthing point instead of the sensor ground incase of short circuit? Thanks.

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**Author:** ![FloorItGarage](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/flooritgarage/32/61_2.png) [@FloorItGarage](https://community.ecumaster.com/u/FloorItGarage)\
**Post date:** [March 15, 2025, 8:48pm UTC](https://community.ecumaster.com/t/12v-vehicle-speed-sensor-connection/3338/4 "2025-03-15T20:48:28Z")

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yeah that’s my standard practice. 5V sensors get sensor ground; 12V get power ground.

I’m pretty sure all Ecumaster inputs are 12V safe, but just in case I like to separate

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**Author:** ![seant](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@seant](https://community.ecumaster.com/u/seant)\
**Post date:** [April 11, 2026, 6:32pm UTC](https://community.ecumaster.com/t/12v-vehicle-speed-sensor-connection/3338/5 "2026-04-11T18:32:43Z")

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Following on from setting up my vss, that’s all working correctly and I have got correctl km/h speed showing on emu dash3 via an android tablet I’m using as my dash display. Question is the a very basic way to change to display mph also change from kpa to psi for map readout. Running emu black v2 - step by step would be great if someone has the time Thanks