Spd sensor question...

[ILikeMy240sx]

1996 Nissan 240sx 77k miles

I got a check engine light for the spd sensor... Of course spdometer worked on and off so I got a new sensor and a new gear... Installed them.

As soon as I started the car the speedometer stayed zero until 4th gear. It worked for a while then it went to zero for a split second then worked for a while then dropped to zero and stayed there...

I pulled the engine code and spd sensor was not one of them...

If I wanted to check the harness that connects to the spd sensor, do I check for continuity or resistance? how?

Thank you.

[s13sr20chris]

let me just start by saying...90% chance of bad speedo head.

ok, the speedo wires are red and red/yellow right? pull speedometer and check those wires in the back(pins 28 and 35). once you find them and check continuity(you will prob have it) check for a/c voltage across them when you are driving(car jacked up) or just spinning the sensor really fast. if you have a signal then your speedo head is bad.

[ILikeMy240sx]

You are so helpful in everyway!

Thank you. I've searched through the FSM and found this and it's just like what you said. But I have one question about it... At step D it says to measure the resistance between terminal 1 and 2 but from the picture it looks like they are measuring the resistance of the harness but not the speed sensor it self...

Why would they tell you to change the spd sensor if the resistance of the harness is wrong?

Ive measured the resistance of the spd sensor it self and I had a .30 Ohm reading.. which is WAY off from 250Ohms mentioned..

[s13sr20chris]

yeah, they are telling you to measure the resistance of the sensor itself not the harness. if your resistance is wrong then it is in the sensor.

[ILikeMy240sx]

Thanx.

That's odd because the old sensor and the new sensor both had the same resistance. .29 Ohms...

Can anyone double check the resistance of the spd sensor before I go off and buy another one? *sigh*