Elise K20 on K100 OBDII port wiring

[EliseK20R]

Hi I have an Elise K20 with a JR Supercharger.

I want to get the Lotus OBDII port to read the Honda K100 ECU.

The ECU is a UK spec CTR EP3 PRA ECU.

I have done lots of reading but I don't seem to be able to get the port wired up correctly.

So far I have disconnected wire 58 out of the Lotus ECU (Pin 7 (K-Line) of the Lotus OBD) & wired it to pin E23 (K line) of the Honda ECU but this does not allow my Autel MK808BT code reader to read the Honda ECU still?

What else do I need to wire into the Lotus OBD port from the Honda ECU? Pics below to help.

05-elise_ecu by

RSX ECU pinouts C D E by

[Spunkster]

I would recommend that you find the factory service manual to see how it needs to be wired.

[Arno]

Disconnect the "L" line from the K4 ECU. Most OBD readers get confused by that being present and a different ECU alltogether :)

All that's normally needed is hooking E23 from the Honda ECU up to the K-line wire that was on the K4 ECU and disconnecting the L-line one (pin 73)

And of course check continuity from the OBD plug in the footwell to the ECU pin. Esp. the footwell end can be damaged fairly easily.


Bye, Arno.