If you did an OBD1 B18C or B16A swap into your 5th gen Civic VX, chances are you are throwing code 41 if you haven't converted the Oxygen sensor over to operate in the 4-wire way your ecu (like a p28, p30, or p72) is expecting.
If you have an automatic ECU, read this first: Convert a Honda ECU from Automatic to Manual
Situation:
OBD B-series Swap into EG Civic VX
Civic EG VX harness used on B-series engine
A b-series will not run off the 5-wire, mostly for the computer reasons.
First, pick up a 4-wire o2, found in just about every other civic besides the 1 or 2-wire equipped ones. These can be found at the local auto parts store pretty cheap.
Now you have a 4-wire ecu and O2, but a 5 wire harness.
The easiest way to do this is to simply ignore the Vx harness and run the wires straight from the 4 wire plug up to the ecu. Use your own discretion as to how clean you want to make it, and re-pinning the cannon plug is an option for a cleaner install.
O2 Sensor Input - WHT to D14 (needs to be a shielded wire)
Heater Control - BLK to A6
Sensor Ground - GRN to D22
Sensor Voltage - BLK to A25 or B1 (both are 12-volt sources, so either works fine.)
If you are using an obd2 ecu, check out our ECU Pinouts in the reference section to get the pinout locations.
If you have an automatic ECU, read this first: Convert a Honda ECU from Automatic to Manual
Situation:
OBD B-series Swap into EG Civic VX
Civic EG VX harness used on B-series engine
A b-series will not run off the 5-wire, mostly for the computer reasons.
First, pick up a 4-wire o2, found in just about every other civic besides the 1 or 2-wire equipped ones. These can be found at the local auto parts store pretty cheap.
Now you have a 4-wire ecu and O2, but a 5 wire harness.
The easiest way to do this is to simply ignore the Vx harness and run the wires straight from the 4 wire plug up to the ecu. Use your own discretion as to how clean you want to make it, and re-pinning the cannon plug is an option for a cleaner install.
O2 Sensor Input - WHT to D14 (needs to be a shielded wire)
Heater Control - BLK to A6
Sensor Ground - GRN to D22
Sensor Voltage - BLK to A25 or B1 (both are 12-volt sources, so either works fine.)
If you are using an obd2 ecu, check out our ECU Pinouts in the reference section to get the pinout locations.
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