92-95 Civic CX Up Shift Indicator Troubleshooting

If you have a 92-95 Civic CX model and are experiencing a problem with the up shift indicator on your gauge cluster illuminating incorrectly after an ECU change, this is due to the variances on OBD1 circuit boards between the stock Honda Civic CX ECU and all other models

Honda Civic CX P05 ECUs use ECU pin D18 to send a ground signal to the up shift indicator bulb in your cluster.

If your Honda Civic CX is using a non Honda Civic CX ECU and you are experiencing an issue with the up shift light staying on due to using a different ecu, simply cut or disconnect the wire at your Obd1 ECU pin D18 or remove the up shift bulb in the clusters.