Hello, I was hoping someone could help me identify the IC on board below. Normal googling did not produce any actionable results.




I don’t know much but it is used to convert a vehicle speed sensor output into 4000 pulses per mile. Only 4 wires are used - 12 volts, ground, vehicle speed sensor input and 4000 pulse per mile output.

Any info would be helpful.

-Mike

 

Then it will be an "Inhouse chip" made for the manufacturer only.

What input signal is it getting, a voltage like 0 to 5V, and giving out 4000 pulses?

 

Thanks DodgyDave, that makes sense. From what I know so far the input is 0-5 volts and output is 4000 pulse per mile sign wave that’s AC current but I don’t know the transfer function. I saw people online do something with an RS232Max to accomplish something similar.

I was hoping the chip was an off the shelf item, oh well. Hopefully the board and its components last for a while longer. It was located close to a heat source and has looked better.

-Mike

 

Your only solution is to use a Pic micro or Arduino, and make your own modified circuit.


Trying to get my head around this,,

Does the chip takes a a signal from the speedometer!?

What is the 4000 pulses going to?

My guess is it's taking the 4000 pulses, and giving out 1-5V.

 

The chip take 0-5 volts from a VSS (vehicle speed sensor) mounted in the transmission of a car. It outputs a signal to the speedometer that interprets it and displays the speed. The signal is 4000 pulses per mile sign wave using AC current. At least that what I’ve found so far doing some research.

It’s a little odd.

 

I’ll do some more research and maybe pick up an extra VSS and spin it with a drill to double check what comes out of it and what comes out of the chip.

 

The chip take 0-5 volts from a VSS (vehicle speed sensor) mounted in the transmission of a car. It outputs a signal to the speedometer that interprets it and displays the speed. The signal is 4000 pulses per mile sign wave using AC current. At least that what I’ve found so far doing some research.

It’s a little odd.

Are you sure you are going the right way on the signals? Aren't most VSS signals AC and the signal to the speedo pulsed DC? At least that's what I've always heard about this.

 

@Mike in Boston Can you photo the back side of pcb? Who is the manufacturer of module? It may give clues to the manufacturer of the IC.

Then it will be an "Inhouse chip" made for the manufacturer only.

Most of these are just relabeled ic's so there is actually still hope in finding it or a substitute. Unmasking it sometimes is simple enough.

Are you sure you are going the right way on the signals? Aren't most VSS signals AC and the signal to the speedo pulsed DC? At least that's what I've always heard about this.

I don't know vss well but I think your right.
The cluster will use dc signal but I'm not sure where its converted. (cluster board or externaly),
Perhaps this IC could be a ac/dc converter?

 

I don't know vss well but I think your right.
The cluster will use dc signal for sure but I'm not sure where its converted. (cluster board or externaly),
Perhaps this IC could be a ac/dc converter?

My guess would be one of the converters that takes a new VSS tranny and makes it work a analog speedo.

 

Are you sure you are going the right way on the signals? Aren't most VSS signals AC and the signal to the speedo pulsed DC? At least that's what I've always heard about this.

That’s how I understand it but I will research more.

 

Here’s a photo of the back. The board came with an aftermarket car ECM I installed to retain the speedometer functionality. The company that provided it was a place called White Racing (whiteracing.com). The work it is doing was originally done by the factory Chevrolet ECM.

 

You can't tell anything from this picture,, i think the speed sensor is giving out pulses upto 4000 per mile, (400 per tenth mile)
and the chip is probably giving out a voltage 0 to 5V depending on the speed, and must give out a pulse every tenth or full mile to the ECU.???

 

What is needed in this is the type of VSS is in the transmission, 2 or 3 wire. They each put out a different signal. If the circuit shown is an add on box, before the ECU, it is probably used to change the type of signal. From what the VSS is putting out to what the ECU is expecting.

A link to the two commonly used types, 2 or 3 wire - https://www.speedwaymotors.com/the-toolbox/testing-2-and-3-wire-speed-sensors/28754