PLX Wideband Wiring Instructions

Remove the stock oxygen sensor and install the wideband O2 sensor.

Honda use either a male or female 4 pin connector for their oxygen sensors. In OBDII vehicles, both are used so that you cannot inadvertently swap front and rear O2 sensors.

Closed/Open Loop - Wideband readings datalogged in S-Manager:

• Red wire Power cables for the PLX wideband - connect to switched power in the fuse box
• Black Ground - Attach to solid chassis ground
• White 0-5V Output from wideband - connect to ELD input making sure that the ELD is no longer connected to it (ELD is pin D10 on an OBD1 ECU)
• Gray 0-1V Output for narrowband - connect to white wire from stock O2 plug per instructions below
• Some ECU's may need to have resistors R136 and R138 removed to improve wideband reading accuracy in the software.

You can make an adapter (using the plug off a dead O2 sensor) that connects the 0-5V wideband output to the stock oxygen sensor plug. The adapter plug does two things. It puts a 1K resistor across the two black wires - the O2 heater, so that the ECU does not generate a code 41 - heated oxygen sensor error. Even if you do get this error the ECU functions normally.

The other two wires, typically green and white are ground and signal, only the signal wire (white) is used.

S-Manager Setup

In Parameters go to Closed Loop, click on the Wideband Lambda input source select the source you wish to use.  You must choose the source based on how you have wired the Wideband into the ECU.  If the wideband display reads different than the datalogged readings, then use the voltage offset field to enter either a negative or positive voltage until they match.