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Speed sensor might be bad

28 April 2005
I am having the following problems on my 91' NSX:
1. My Electronic powerstering (EPS) light is on. This disables my powerstering.
It came on just going around a normal corner.
2.The green box around my drive [D] light (like [1], [2], [3], [D]) flashes and the speedometer drops to 0 mph.

Since the EPS is speed sensitive I think the "speed sensor" might be bad and causing the EPS to come on and disable the powerstering
the Speed sensor is about 140$
any thoughts?
Think I should repace it and roll the dice
better Ideas? :confused:
Oh ya, I can reset the computer and the EPS light goes off.
stays off for a while and seems to come on again when the speedometer freeks out again.
My 92 Legend had a bad speed sensor. The symptom was the green box around the "D" (drive indicator) flashing and the TRANSMISSION would not shift properly not the power steering unit quitting. If it's built with the same ideas in mind as the regular Acura line then it affect your tranny.


I think you are on to something:). It woul dbe best, since this is intermittent, if you can get a replacement speed sensor from someone and give it a shot. The speedo doing what it is doing, does implicate the speed senor signal for sure. Also check the wiring for the speed sensor, connector etc.

Got the same exact problem as yours a while back i.e. eps light on-power steering off, check engine lights on, "D" flashing and speedometer having a mind of it's own. Changed the speed sensor and everything is back to normal...
I had a similar issue this weekend on a 500 mile drive in my 92' 5 speed NSX. My traction control light would come on, the speedo would be all over the place and the trac control computer was cutting power as if there was wheel spin....can this be the same speed sensor?

This only occured after 150 miles of highway and then about 40 miles of city driving. On my return trip the same issue occured approx 170 miles into the trip. I was thinking it might be a temperature issue as well, at least that seemed consistent. On the return trip the same TCS light came on and corresponding power reduction occured but only during 1st and 2nd gear driving. After 2nd gear the problem dissapeared only to return at the next stop light.

I am a motorcycle mechanic by trade and that was the first thing that popped into my mind.

Is it possible the oil fouling could just be cleaned with solvent and the sensor does not need to be replaced? If it is the opionon of the the NSX tech Gods that I should replace the sensor anyway I will do so.

In your case you can pull the codes and see if the results will help you. There is a service manual download on the NSXPrime opening page (left side). Download it and have a look.

Check the TCS codes and see what it tells you. I will say though since the speedo went whacky it does sound the same:).