low voltage

Closed Thread Subscribe

Thread Tools

Search this Thread

Aug 21, 2012 | 01:38 PM

bh76

Thread Starter

5th Gear

Joined: Aug 2012

Posts: 9

Likes: 0

From: nwi

low voltage

can anyone tell me why i have low voltage to the speed sensor on my 2004 sportster? i tested the red wire that goes the sensor and it was very weak what would cause this?
thanks

Aug 21, 2012 | 02:48 PM

oldairboater

Ultimate HDF Member

Joined: Jan 2008

Posts: 7,476

Likes: 5

From: Republic of Texas

Bad wire or bad connector on either end. Check the voltage if you can at the beginning connector. I don't remember what that connector is called and I am too lazy to drag out my manual. That way you rule out meter error and have eliminated or concluded where the problem may be. Had to drag my meter out and check voltage to a coil the other day. Once I eliminated the question of power to the coil I zeroed in on the coil itself.

Aug 21, 2012 | 07:41 PM

bh76

Thread Starter

5th Gear

Joined: Aug 2012

Posts: 9

Likes: 0

From: nwi

i tested everything i could and i seem to have low voltage coming out of the icm? but i still dont know why. any ideas? bad icm? can it be bypassed?

Aug 21, 2012 | 08:10 PM

soft 02

Seasoned HDF Member

Joined: Mar 2007

Posts: 66,948

Likes: 4,573

From: TOAK western branch

Correct me if I'm wrong but speed, crank, and TPS sensors only have 5v at the sensor. This is why a good ground is so critical. Could be wrong though.

Aug 21, 2012 | 09:05 PM

harleycharlie1992

Unofficial HDF Chaplain

Joined: Dec 2009

Posts: 21,160

Likes: 18,082

From: san diego

Quote:

Originally Posted by soft 02

Correct me if I'm wrong but speed, crank, and TPS sensors only have 5v at the sensor. This is why a good ground is so critical. Could be wrong though.

this is correct. this is reference voltage and it should be 5-5.5 volts check for voltage drop at ground but if speedo isn't working, my guess is speed sensor, kinda common. be sure to use a GOOD volt meter, not that one from radio shack, ( unless its one of their good ones!) don't use a 20 volt meter looking for problems. get a good one,and it won't give you false readings that make you chase your tail

Aug 22, 2012 | 08:55 AM

bh76

Thread Starter

5th Gear

Joined: Aug 2012

Posts: 9

Likes: 0

From: nwi

i have replaced the speed sensor and checked it for shavings. i think it is most likely a ground also i just dont know which ground is for the icm. the voltage is very low from icm