I'm looking into the 3.89 gear install but I know that us 02+ treps have to have the speedo correction because putting in the gears cause like a 6% diff in the reading. Well, I'm in talks with two different companies Yellr who makes the yellow box & Heal Tech Electronics who make the SpeedoHealer. The guy I'm talking to from Heal Tech has said this after I asked him for a SpeedoHealer for us 02+ treps "We don't have any technical information about your car, unfortunately. Basically we need to know what kind of speed sensor it has.
At first, if possible, please check whether it has a 2-wire or 3w speed
sensor. If you have a wiring diagram, that may help."
98-Eser had told me "Neither. The speed is computed from the tranny sensors, the signal goes to the PDM/TCM box, and then via electric wire to the speedo." So this is what I told Heal Tech & Yellr.
The employee from Yellr had said, "The transmission sensors are normally either a 2-wire or 3-wire sensor. What does your sensor look like?" But the guy from Heal Tech told me to do this "Ok, set a voltmeter in DC 20V setting.
Turn ignition on but have the engine off. Rotate the drive shaft slowly.
Measure the voltage on the signal wire that goes to the speedometer.
Does the voltage cycle from e.g. 0V to 5V repeatedly, when the shaft is rotated?"
Here are the wiring diagrams:
Does anyone have an answer to my confusion?