New for 2019, all wiring products have undergone a significant upgrade featuring Tefzel® mil-spec wiring and Raychem DR-25 heat shrink tubing for the ultimate in heat, chemical, and abrasion resistance. This replaces the previous generation which utilized standard hook-up wire and flexible expanding sleeve. While this has led to an increase in cost, the motorsport-grade material and construction techniques ensure flawless performance, extreme durability, and rock solid reliability for these critical, aftermarket sensor installations.

BW Tuning mil-spec harness
PnP Wideband AFR Integration Harness for Subaru WRX/STI

$65 plus $7 shipping US domestic

Most Subaru turbo vehicles do not have wideband O2 sensors that can be used to tune the vehicle accurately. This harness allows you to integrate aftermarket wideband gauges and sensors into your factory ECU, allowing the ECU data logs to contain wideband AFR data. This will make your logs "complete" and able to represent the full picture of what the engine is doing. Harness is custom made with 8 feet of wire and high temp heat sleeving for an OEM look. It provides power and ground as well, making gauge installs easy (no more hunting for power and ground wires, and no messy cutting/tapping). Totally reversible in case you want to go back to stock.

Requirements: 2002-2017 STI, 2002-2014 WRX. Wideband gauge kit with a 0-5v analog output (most popular: AEM, Innovate). Aftermarket downpipe required. **Note that 2002-2005 WRX must use TGV connector (TGV deletes required) for integration.

Instructions: This harness plugs into the Subaru factory rear O2 sensor engine harness connector and can be used to in two ways:

  1. Existing wideband installations, connect your wideband signal wire to the yellow wire.

  2. New wideband gauge installations, connect all three wires in order to fully power the gauge and integrate the readings into your ECU.

NOTE: this product requires custom tuning (disabling rear O2 sensor CEL codes and fuel trimming logic). Factory rear post-cat O2 sensor can be removed from vehicle and bung blocked off. This will not work with stage 1 setups (stock downpipe).

Common wiring notes:

  • AEM UEGO (basic): red (12v power), black (ground), white (0-5v signal)

  • AEM X-Series UEGO: red (12v power), black (ground), white (0-5v signal), brown (signal ground. MUST BE GROUNDED for signal to work!)

  • Innovate LC-1/LC-2: red (12v power), black (ground), yellow (0-5v signal)

PnP ECF-1 Harness for Cobb FlexFuel 06+ WRX, 07+ STI

For cars with stock TGVs and partial ECF-1 integration (FlexFuel, Wideband):

$99 plus $7 shipping US domestic

For cars with TGV deletes and full ECF-1 integration (FlexFuel, Wideband, Fuel Pressure)

$125 plus $7 shipping US domestic

​Plug and play FlexFuel for Cobb AP has never been easier or more fully-featured than now. The ECF-1 by Innovate Motorsport (sold separately) provides not just FlexFuel but also wideband AFR and fuel pressure monitors. Each of these three inputs can be integrated into the Subaru stock ECU via the Cobb AP V3 which effectively supercharges the ECU's ability compared to stock. FlexFuel enables the car to run on gasoline or ethanol in any mixture, and automatically adjust power and drivability based on the fuel in use. Wideband integration allows for AFR data to be in your AccessPort data logs for easier tuning. Fuel pressure integration with the Cobb AP V3 allows for fueling correction based on fuel pressure variation, a feature not available otherwise.


Using the ECF-1 and this PnP harness makes the installation FULLY PNP without messy cutting and splicing of any factory wires. Fully reversible if ever needed! Harness is custom made with OEM Subaru connectors and high temp heat sleeving for an OEM look.

Requirements: 2006+ WRX, 2007+STI. Cobb AP V3. Innovate ECF-1 kit.