Road speed sensor fault testing

Road speed sensor fault testing

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s p a c e m a n

Original Poster:

10,752 posts

147 months

Sunday 23rd April 2017
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My speedo and odometer have stopped working, rovergauge also shows no road speed. I've got a 2 pin sensor on the differential type setup that is as close to the teeth as I dare.

Never tested one before so I just wanted to make sure that I'm not missing anything as I've no idea what signal these send out. Stuck the car up in the air, wired up my multimeter to the sensor and run the car in 5th gear at idle. That's fast enough to get a signal from the sensor isn't it? Flicked around the dial and no ac/dc or ohm registering. Dead isn't it?

I've just checked the grey and black wires going from the sensor plug to the box under the dashboard and they showed fairly good continuity considering it was a 4 meter run involving speakerwire to make a circuit hehe

Any way of testing the little black box of bodge with zero electrical skills?

Thankingyou smile

Steve_D

13,737 posts

257 months

Sunday 23rd April 2017
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When you say the sensor is close how close bearing in mind it should be about .010"?

It should produce a small voltage. It gets larger with higher speeds.

Steve

Penelope Stopit

11,209 posts

108 months

Sunday 23rd April 2017
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You should get a reading when set to one of the OHMS ranges but I don't know what the figure should be
Ask someone with the same sensor to test theirs and pass on the figure to you

Kbee

163 posts

104 months

Sunday 23rd April 2017
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Just had a problem with mine put ur meter on ac voltage this will show if oyu are getting pulse which is what the speedo operates on