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For certain K-swapped vehicles that use a K-series transmission with a CSS type speed sensor (Countershaft driven Speed Sensor), a non-working speedometer is a common issue associated with this transmission. This is a text book case when using an 02-04 KPRO ecu with a 05+ CSS type K-series transmission. The 02-04 generation K-series ECU inherently looks for a mechanical type VSS (Vehicle Speed Sensor), but when a KPRO daughterboard is installed onto an 02-04 K-series ecu, it is capable of converting the VSS signal to a CSS signal INTERNALLY with the aide of this speed sensor resistor mod -and a few other required steps. But most importantly, having this resistor mod in place is mandatory in allowing the internal conversion to fully work thus allowing the speedometer to work properly.

The speed sensor mod is typically performed in-house by Hondata during a KPRO V4 installation job. It’s two small modifications they add which helps amplify the speed sensor signal and allows a V4 (and V3) KPRO to internally convert a mechanical VSS signal to a digital CSS signal, thus allowing the speedometer to work – again – with additional other required steps. There’s a visual way to check if the two mods are in place or not (see below).

We’ve learned that authorized Hondata KPRO installers may or may not be aware to perform this resistor mod during a KPRO daughterboard installation.

The current way of converting a CSS signal with an 02-04 ECU is by way of using a speed sensor conversion device (box) such as a K-Tuned All-In-One Converter or Dakota Digital converter box, which are great devices by the way. In fact, the K-Tuned AIO converter is a much needed device when using an 02-04 KPRO compatible AUTO ecu used for a manual K-swap. This resistor mod is not needed for auto compatible KPRO ecu’s as those ecu’s completely bypass the CSS settings anyways defeating the resistor mods purpose.

Why would I need this mod?
If you’re using any of the following manual CSS type transmissions and you want your speedometer to work properly, the speed sensor resistor mod is NECESSARY:
K20Z1 trans
K20Z3 trans
K20Z4 trans
JDM FD2 & FN2 K20A trans
CL7 Euro R K20A trans
Any 5/6-spd Accord/TSX K24A or K24Z trans (excluding CRV & Element 5spd trans)

What’s the difference between a CSS & VSS transmissions?
VSS transmissions are typically 02-04 era (ie. 02-04 RSX/02-05 EP3 Civic Si) with the exception of the 03-11 Honda Element & 02-06 CRV 5spd transmissions; but the VSS era transmissions have their sensor located on the back section of the transmission casing just above the differential. Its a 12v sensor and has a mechanical gear on the end of it that meshes with a speedo gear that is on the differential. A CSS is a 5v hall-effect [magnetic] type sensor that is located on the frontside of certain 05+ K-series transmissions (ie. 05-06 RSX, 03-05 Accord, 04-08 TSX, 06-15 Civic Si). It pulls a speed sensor reading by way of magnetic pulse from 3rd gear. Tbh, CSS transmissions have been a royal pain to deal with in the earlier days of K-swapping.

Which KPRO ECU’s does this mod work on/for?
The speed sensor resistor mod is STRICTLY for 02-04 KPRO compatible 5/6-speed manual transmission ecu’s. It will not work for KPRO compatible AUTO ecu’s from what we’ve tested in-house. Auto compatible KPRO ecu’s require specific wiring changes and KPRO Kmanager speed sensor setting changes that completely deviate away from CSS settings.

Do auto compatible KPRO ECU’s need this mod?
As mentioned above, unfortunately, auto compatible KPRO ecu’s are not capable of handling a CSS conversion internally due to required wiring and Kmanager tune changes these ecu’s require. However, you can use a K-Tuned VSS AIO converter in conjunction with an auto KPRO ecu to get your speedometer to work! We’ve successfully tested this in-house.

What changes in the KPRO software (Kmanager) need to be made after this resistor mod is performed?
Its simple – first download your existing tune, then go into the PARAMETERS window, click on the MISC button-tab, look under the SPEED SENSOR options and tick the Countershaft driven Speed Sensor button then upload. Note that a wiring mod is required as well; a wire ran from ECU B11 to C101-pin3 (thank you VTEC Academy for this info!).

What other versions of KPRO does this resistor mod & internal CSS conversion work with?
In our testing we’ve found it works with the V3 KPRO (red daughterboard) and of course the V4 KPRO (white daughterboard). It will not work with V1 or V2 KPRO’s (green daughterboards).

How can I check if my 02-04 KPRO 5/6-speed ECU has this mod in place already or not?
With the top cover removed, look in the following quadrant on your KPRO ecu (just above the RM760 address). Note: the surface components are very small, be like a boomer and use your cell phone camera to better view the area:

Fee (w/incl standard return shipping): $45
Service: add two modifications to KPRO ECU for speed sensor mod.

 

Please use the contact page to inquire for any of these services.