MapDCCD Wheel Speed Sensor: Link to Website: http://mapdccd.com/vss.html Link to Manual: http://mapdccd.com/media/MapDCCD_wheel_speed_sensor_signal_processor_install_guide.pdf Why would you need this? This module is used when you swap a newer transmission (that does not have a speed sensor built into the housing) into an older car that does not have a way to pull the vehicle speed from the ABS (like newer cars do). Specifically putting an 08+ transmission (5MT or 6MT) into an 02-07 (or older) car. As more and more 08+ parts are hitting the used market (often in better condition than 02-07 parts) it is likely that this will be needed more frequently. What are the available versions and the differences? There will be two versions of this module available. The first one, which I have, is more basic and is used simply to feed a speed signal into the ECU. It can use one or two wheel sensors, and only has a single output (vehicle speed to the ECU). The second model will be able to use up to four wheel sensors and will be able to output to the ECU and to the MapDCCD controller (if installed). The DCCD integration will detect wheel slip and adjust DCCD locking accordingly. Photos: Initial Impressions: This VSS unit is very small and well packaged. It is a single PCB with surface mount components on one side and easy to read labeling and logos on the other side. The board is protected by a transparent plastic case (similar to a very thick heat shrink wrapping). It has a socket connector on one end of the board and two adjustment buttons on the other end. The wire connector for the basic model has 7 individual wires coming off of it. Two of them (secondary wheel sensors) had heat shrinked ends because they are not necessary. If you wanted to use these, you would cut/strip the wires. For single wheel input all you need to connect is ground, switched power, positive and negative VSS inputs, and the VSS output to the ECU. The module itself is very small and light and can be mounted anywhere that is convenient (I have mine zip tied under the dash). Overall I'm impressed with the small form factor and great level of quality in the product's physical appearance. The labeled wire locations is a huge plus for ease of install. The socket connector is also great, because you can leave the module out on your workbench while you get all the wires run and connected, and then simply plug the module in when you're done. Installation: Black/White = Ground (ECU Ground) Red = Power (12V Switched Power) Yellow = VSS Out (Connect to ECU VSS input - pin A1) White: Wheel 1 - (White Wire at ABS Sensor) Brown: Wheel 1 + (Black Wire at ABS Sensor) White: Wheel 2 - (White Wire at ABS Sensor) Brown: Wheel 2 + (Black Wire at ABS Sensor) The first five of these connections are mandatory for functionality. The last two can be connected to add redundancy and slightly increase speedometer response and accuracy, but they are purely optional. The black/white wire goes to chassis ground (I grounded mine near the ECU). The red wire I ran to a Add a Circuit (fuse tap) going to a switched 12V circuit in the fuse box (I used the rear wiper). You could also splice into the clock wiring to reduce the amount of extra wiring that needs to be run. I already had wires run to the fuse box, so that was the easiest for me. Once the module has power and ground, then it just needs the input and output signals to be connected. For the input signal the brown wire and white wire need to be run through the firewall and into the engine bay. With the glove box out there is a grommet that can be used, and once pulled through the wires will reach the front passenger side signal. I tapped in to the ABS wires just after they entered the engine bay through the fender. There is a white wire and a black wire (for 2002 WRX). Match up the white with white and black with brown. Alternatively, you could run the VSS input signal wires to the ABS module that if further forward in the engine bay and use the main harness up there. The location I used is a bit hard to reach, so the more open space may be preferable to some. It is also easy to tie into two or more signals at this point. The last thing you need to connect is the VSS output to the ECU. The yellow wire off the VSS goes to pin A1 on the ECU (for the 2002 WRX). This can be accessed by pulling up the passenger front carpet and removing the plate over the ECU. Review: The installation of this unit was very straightforward (and was especially easy for me due to the fact that I previously had a different module installed). The MapDCCD VSS module does not require any special precautions to be taken when choosing input power, ground locations, or VSS inputs. The VSS input wires do not have to be run out to the hub, and they do not need special shielding. Power and ground can be connected just like any normal gauge install. No secondary ground is required. After it's all hooked up you can start up the car and go for a drive. The buttons on the module can be used to increment the speed signal up or down to calibrate it. I checked it compared to a phone GPS app and it was within 1%, (which was great because my summer tires are slightly taller than stock, but my winters are stock size) so I didn't have to make any adjustments. After that is set, you can tuck the module away and finish putting together your carpet/dash. I've had this unit installed for a couple weeks now and it has been flawless. Unlike other units that have issues with signal integrity (and can often give erroneous 0mph or even 150mph readings) this unit has been working without a single hiccup. It is responsive, accurate, and works as expected every time. I have not been able to make it falter no matter what I have done. The circuit appears to be far more robust to weak or varying input signals and can handle them without issue. Overall, this is an A+ from me. If a VSS module is something you need, then this is the way to go!
Thanks Todd! FYI - The website has now been updated with the full info on the VSS. Link to Website: http://mapdccd.com/vss.html Link to Manual: http://mapdccd.com/media/MapDCCD_wheel_speed_sensor_signal_processor_install_guide.pdf
