Speed Signal Sensor & Headlights
 

Well i hate to do it.. but i have to start a thead instead of learning vicariously

I have searched, and have been visiting this site for around 2 years.. ive all but rebuilt my 7 which i initially saved from the local wreckers with nothing more then this forums search function and the various fsm's available. im by no means a mechanic so this is a testament both to the rx7 and to this forums members.

so help a guy out an wait till i get a good answer b4 u flame me

i frequently get the 2 beep speed signal sensor warning. Tends to happen more when the headlights are on, an often stops if i turn them off, starts when i turn em back on. I noticed it starting an stopping after hitting bumps which leads me to think a wire is loose or some such thing, however i dont know where to look. so far my searching has mainly yielded that there is a speed signal wire that goes into the ECU, but i dont know where else to look for a solution. Any info on where to look to trouble shoot such an issue would be greatly appreciated. What sends the signal to the ECU would be a good start. Also possibly of value is that the sound is not consistant.. the volume and tone vary to a degree. can low voltage cause this as my grounds are piss poor an next on the list to fix.

I don't know about s5's, but on an s4 there is NO speed signal into the ECU. There is a speed signal that goes into the Power Steering Computer, the instrument cluster, and the cruise control switch. There might be others I forgot about.

signal comes from the speedo. Not sure what to say except to try re-wiring it and check for cold solder joints.

Yep, the speed signal comes from the instrument cluster, because the signal sensor is in the speedo. ;) It goes out to the power steering control unit, cruise control unit, AAS control unit (if AAS is fitted) and 4AT control unit (on autos). Definitely nothing to the ECU though.

If you put a multimeter that can measure frequency on the speed input wire on the P/S control unit, you'll be able to see if the signal is bad there, but that won't tell you if it's a bad sensor in the cluster or a lose wire. It's a bit more hassle, but pulling the cluster and putting a meter on the wire at the cluster plug will show you if the sensor's okay or not.

Go drive your car. Engage the cruise control. If the cruise works.............well you can figure it out from there.

DOh.. yeah, car is an s4.. 87 NA.. cant believe i forgot to specify..

power steering computer is disconnected as i swapped in a manual rack

cruise ctrl has never worked as far as i know but i have an extra switch and an extra speedo so ill try those to start.. thanks guys..

but why the headlights?

If the power steering control unit is disconnected then it won't be making any warning beeps because it has no power!

So what exactly are you hearing?

Sounds like the beeping that tells you when you've left your lights on and the ignition is in the off position... bad connection at the body cpu?

an then the lightbulb went off in my head !!!

thats what kept confusing me when i searched this.. it always came back to the power steering computer, but it was disconnected. i rarely shut the car off with the lights on an had forgotten about the beep. body cpu turned the lightbulb into a question mark.. wheres it at? spose the haynes guide will have that

Not to my knowledge but... it's on page 9 in the PDF here:

http://www.teamfc3s.org/main/factory...CAL_SYSTEM.pdf

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