RX3 Connectors

There are 6 unused connectors on the RX3.

The easiest to characterize are the two connectors under the left rear side panel. They are 12v connectors switched by the two position slide switch between the kill switch and the starter button on the right hand grip. This switch has two positions, A1 and A2. A1 turns one of them on, A2 turns the other one on. However you can't have both of them powered at the same time, and in order to get to A2, you have to go through A1 (so A1 goes on and off as you switch A2 on and off). The connectors seem to be standard 2.8mm molex type connectors and they are easily found on eBay. Using a small relay it would be quite easy to make the switch positions (A1 and A1+A2) rather than (A1 or A2). This circuitry is not found on the RX3 wiring diagram. It's an addition because the Chinese RX3 can switch the headlight and running lights on and off. In the US the headlight is always on so the two position switch used to turn it on and off on the Chinese bike is now used to switch the two auxiliary connectors on and off. The switch actually is on the wiring diagram (marked "switch, illuminator") but the connections are wring and refer to the chinese model of the bike.

The two connectors at the instrument panel are intended to connect with the accessory power outlet system sold by CSC. The two pin connector has 12v and ground pins which are live whenever the ignition is turned on. The 4 pin connector has no live power connections unless a "dongle" is plugged into the 6 pin connector found under the right rear body panel seat. This connector seems to be a 6 way 6.3mm connector While no description of the dongle is given (CSC refer to it as a "green resistor"). In fact it's presumably a 5v regulator system since USB ports supply +5v of regulated power. Power would only need two connectors so perhaps the other two lines are voltage feedback from the USB socket used to sense the voltage there, feed that information back to the regulator which then adjusts the regulator output voltage to compensate for any voltage drop on the power lines. This would keep the voltage at the USB connector at exactly 5v, regardless of the power drawn. The 12v outlet voltage will fluctuate depending on the state of the battery and the amount of current being drawn. It will typically be at a little over 14v with the engine running and no load on the circuit. The other two lines could also be used to signal available current draw to devices that look at those lines for information. Some devices look for a short while some Apple devices look for specific voltages.

I have not yet been able to identify the exact identity and part number of these connectors. There are dozens, if not hundreds, of similar waterproof automobile/motorcycle connectors on the market, none of which are cross compatible! Note that the two power connectors and regulator assembly connector are not shown on the RX3 Wiring Diagram.

The black 6 pin connector which is found next to the ECU under the panel which is under the rear seat is the "Trouble diagnostic link" which is marked on the RX3 wiring diagram. It carries signals from the ECU module and can output error codes and other information to a compatible readout unit. The wiring diagram show 6 connections to the diagnostic port:

So it should be easy to figure out which pin is which from the wire colors. According to the Delphi small engine service manual, their diagnostic readout unit uses only three of the pins which are connected as shown below:

The other pinouts for the connector are not specified. The KW2000 line (K-line) is the data line and uses a bidirectional serial data stream. However things aren't quite that simple in that there are a bunch of different protocols within the KW2000 envelope. See this explanation of KW2000. To talk with or listen to the ECU you need the correct version of the KW2000 data protocol. The CAN (control area network) lines can be used to communicate with other devices associated with the engine via a serial data network.

Ideally we should be able to simply connect a PC to the K-line via a hardware adapter and with the right software (easy to say, more difficult to do) readout data from the ECU diagnostic port such as error codes and possibly operating parameters of the engine. Going even further and perhaps using other lines, it may be possible to reflash the ECU with different fuel maps.

The ideal solution to reading the output from the diagnostic connector would be if the three active lines could be connected to the appropriate pins of a standard OBDC II connector, a bluetooth OBDC II adapter plugged into the OBDC II connector and software such as "Torque" was able to read the K-line data. Total cost there would be about $15 (plus an Android phone with bluetooth). It's probably too much to hope it would all work flawlessly, but there's always a chance it might. I will be testing it at some point.

Update: I have the Bluetooth OBCD II connector attached to my car (which also used the K-line data transmission protocol) and I'm receiving data on my Adroid smartphone using the Torque program. The next step will be to wire the appropriate pins to the diagnostic connector on the bike and see if any data is detected.