Monday, February 27, 2017

How to check if Hondash will work with my ECU?

Follow these simple steps to determine whether or not the Hondash will work with your ECU.

1. 3 pin diagnostics connector

All Honda car models produced in 1992-1999 (OBD1 '92-'95, OBD2A '96-'99, some models up to '00-'01) that use the 3 pin DLC diagnostics connector, are compatible with Hondash. 
If you can locate the 3 pin diagnostics connector in your car (locations described here), it's the first sign the ECU is compatible

2. OBD Compatibility table

If you've already located the 3 pin connector, you may search the OBD compatiblity table for your ECU to check its OBD version and/or if it was already tested.  Please note that some ECUs may not be in the table, but if the 3pin diagnotics connector is on-board, they are compatible.

3. DLC Connector 3pin voltages

You may also check the voltages on the connector pins, to determine its health status. There should be a 5V (signal wire) pin (with ignition switched on) and a 12V (power source wire) pin.

In case you're not getting 12V voltage on power wire, you should check for blown fuse (Under hood fuse/relay box, nr.43, 7.5A, ceiling light/cargo area light/DLC connector/Power antenna).

Some OBD1 cars ('92-'95) don't have the power wire in the DLC connector. In that case you have to feed 12V power from another available power source in the car, for example cigarette lighter socket. More information here

4. Aftermarket / chipped ECU

If you're using aftermarket or chipped ECU, you should read this post about Aftermarket / chipped ECU to determine the compatibility by yourself. 

5. Modified ECU - Immobilizer Off

If your ECU was modified with IMMO OFF or similar procedure to disable the immobilizer on hardware level, your ECU might not work with Hondash as we've already seen in two instances involving immobilizer mods. This mod seems to disrupt internal communication and communication on DLC port, preventing from sending or receiving valid data.

6. Engine swap

In case of cars with swapped engines which use conversion harnesses (OBD2A to OBD1 or vice versa), the communication with ECU may not work correctly if the wiring is not done properly. In that case you have to make sure that the signal 5V wire (K-line) in the DLC diagnostics connector is correctly connected to ECU pin (K-line) by tracing it all the way to the ECU connector pins, using a pin-out diagram for the ECU as your reference.