kc95sc400
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- Charlotte, NC
Not sure that this info will do anyone any good at all but I have learned a few things in the process of getting a speed signal from each wheel to my Adaptronic e420c ECU so that I can use traction control and launch control and I thought I would share.
Note that this info is based on my 95 SC400 with an Adaptronic ECU but I'm sure that other years of SC400, the SC300 and other aftermarket ECU's are the same.
There are two types of signals generated by different vehicle speed sensors, analog and digital. The Adaptronic e420c ECU will only accept a digital signal. The sensor that feeds the speedo is a digital sensor. This is fine for use with launch control but for traction control the ECU needs at least two speed inputs, one from a driven wheel and one from a non-driven wheel. Although two inputs will work its really better to have the speed of all four wheels input into the ECU to account for things like one wheel peel and speed differences when turning. The problem with the SC's is that the wheel speed sensors are of a reluctor type and put out an analog signal, there are a couple of ways around this fact.
1. This is not tested by me but SHOULD work. I found out a bit too late in my case but something interesting about SC's with ABS and traction control. The speed from each wheel is input into the ABS/traction control computer in an analog form. From the ABS/traction ECU these readings are turned into what the repair manual calls a "pulsed output" and sends them to the traction control ECU on pins FLO, FRO, RRO, and RLO. Yes, there is an ABS/traction ECU and a separate traction control ECU. Go figure... Anyway, I would be willing to bet that the ABS/traction ECU converts the analog signal to digital for the traction control ECU. So one could simply tap into those four wires and be set.
2. This should work but again not tested by me personally. http://jbperf.com/dual_VR/v2_0.html
3. I think Autotronic makes a convertor but I'm not sure.
4. Or, what I did. I made my own analog to digital converter boards. I went to RadioShack and spent about $10 to make four small boards containing the circuit in the attached picture. On my first attempt I put all four circuits on one board, this didn't work out. For some reason it was interfering with the ECU and the car would barely run. So I tried again later and made four separate boards and it works a damn treat. I put the two for the rear wheels in the trunk, they are spliced into the RR and LR wheel speed sensors the wires for the sensors run through the trunk. The two for the front wheels are near the ECU but a bit further away from it than they were before.
I now have speed inputs from all four wheels! I have yet to really play around with the launch or traction control but it should in theory work great.
Anyway, not sure if this will help anyone but this is just some stuff I learned in trying to get traction control to work on my car with my ECU.
Thanks for reading!
KC
Note that this info is based on my 95 SC400 with an Adaptronic ECU but I'm sure that other years of SC400, the SC300 and other aftermarket ECU's are the same.
There are two types of signals generated by different vehicle speed sensors, analog and digital. The Adaptronic e420c ECU will only accept a digital signal. The sensor that feeds the speedo is a digital sensor. This is fine for use with launch control but for traction control the ECU needs at least two speed inputs, one from a driven wheel and one from a non-driven wheel. Although two inputs will work its really better to have the speed of all four wheels input into the ECU to account for things like one wheel peel and speed differences when turning. The problem with the SC's is that the wheel speed sensors are of a reluctor type and put out an analog signal, there are a couple of ways around this fact.
1. This is not tested by me but SHOULD work. I found out a bit too late in my case but something interesting about SC's with ABS and traction control. The speed from each wheel is input into the ABS/traction control computer in an analog form. From the ABS/traction ECU these readings are turned into what the repair manual calls a "pulsed output" and sends them to the traction control ECU on pins FLO, FRO, RRO, and RLO. Yes, there is an ABS/traction ECU and a separate traction control ECU. Go figure... Anyway, I would be willing to bet that the ABS/traction ECU converts the analog signal to digital for the traction control ECU. So one could simply tap into those four wires and be set.
2. This should work but again not tested by me personally. http://jbperf.com/dual_VR/v2_0.html
3. I think Autotronic makes a convertor but I'm not sure.
4. Or, what I did. I made my own analog to digital converter boards. I went to RadioShack and spent about $10 to make four small boards containing the circuit in the attached picture. On my first attempt I put all four circuits on one board, this didn't work out. For some reason it was interfering with the ECU and the car would barely run. So I tried again later and made four separate boards and it works a damn treat. I put the two for the rear wheels in the trunk, they are spliced into the RR and LR wheel speed sensors the wires for the sensors run through the trunk. The two for the front wheels are near the ECU but a bit further away from it than they were before.
I now have speed inputs from all four wheels! I have yet to really play around with the launch or traction control but it should in theory work great.
Anyway, not sure if this will help anyone but this is just some stuff I learned in trying to get traction control to work on my car with my ECU.
Thanks for reading!
KC
