314220 - Subaru Flex Fuel LGT OBXT 10-12

314220 – Subaru Flex Fuel Kit LGT 10-12 (5 Pin)

Legacy GT 2010 - 2012

Outback XT 2010 - 2012

Congratulations on your purchase of the COBB Tuning Flex Fuel kit! The following instructions will assist you through the installation process. Please read them BEFORE beginning the install to familiarize yourself with the steps and tools needed. If you feel you cannot properly perform this installation, we HIGHLY recommend you take the vehicle to a qualified and experienced automotive technician.

IMPORTANT! Installing this kit will require custom tuning or utilizing an appropriate Stage Power Package map if you have a matching mechanical configuration. Please consult with COBB or an authorized ProTuner in your area if you have any questions!

Table of Contents

Parts List

  • Firewall to Ethanol Content Sensor line
  • Ethanol Content Sensor to Fuel Rail line
  • Flex Fuel Bracket and Strap
  • Ethanol Content Sensor
  • 2 x 4x10mm hex screw
  • Flex Fuel Harness and Module (5-pin)

Tools Needed



Hand Tools

Installation Instructions

  1. Park your car in a flat, level area.

  2. Allow the car to sit and cool.

  3. Squeeze the two sides of the plastic clip to remove the fuel lines from the metal bracket.

  4. Unbolt and remove the bracket using your 10mm socket to remove the two bolts.


  5. Utilize a 5/16" disconnect tool in order to remove the top fuel line leaving the middle vent tube and lower line alone.


  6. Install the COBB Flex Fuel bracket in place of the factory one.


  7. Reinstall the fuel hose retainer into the provided square hole on the flex fuel bracket.

  8. Install the short fuel line onto the ethanol content sensor and the line coming from the firewall.


  9. Use the provided COBB strap and small allen head screws to attach the sensor to the bracket, tightening them down with your 2.5mm allen head wrench.

  10. Attach the remaining line to the sensor and the fuel rail.


  11. Turn the key to the on position and check for leaks.

Module Installation

Installation of COBB Flex Fuel Module

The COBB Flex Fuel Module is designed to be bolted to the inter-cooler support bracket and plugged into the COBB Ethanol Sensor, in-line with the factory Rear O2 sensor and Tumble Generator Valve (TGV).

The Rear O2 connector obtains 12V power, and does not alter the O2 sensor signal going to the ECU. The TGV connection allows the motor signals to pass through for those still using the factory TGV's, however the feedback normally used to check TGV position is used to transmit Ethanol content data to the ECU (Engine Control Unit).

Mounting location may vary by customer/ installer preference, however it is recommended to seal any un-used connections from water intrusion, ideally by using the proper connector mate and using plugs to seal the mating connector.

  1. Bolt the Flex Fuel module to the inter-cooler support bracket using the included bolt. Straighten the cables so that they aren't crossed over each other.

    When plugging in connectors, make sure they are fully seated with a "click".

  2. Pass the Flex Fuel Connector through the factory hoses and wiring harnesses and plug it into the Ethanol sensor. Ensure there is no strain on the connector, wiring, or the module.

  3. Pass the TGV Connector through the factory hoses and harnesses to the TGV valve on the driver's side of the vehicle toward the rear of the engine. Especially if on a lift, you may find this easier to do from the bottom of the vehicle where there's a clear path to the TGV. Ensure there is no strain on the TGV connector, wiring, or the module.

  4. Route the Rear O2 Connector to the bottom of the engine bay near your downpipe, then suitably raise and support the vehicle. Never work on a vehicle supported by a jack alone.

  5. Now safely lift and support your car.

  6. Connect the Rear O2 Connector between the factory O2 sensor harness and the O2 Sensor connector.

  7. The O2 connector harness has extra length to work on a variety of vehicle configurations. Using the included zip-ties, secure the harness to the metal lines on the underside of the vehicle and in the engine bay. Ensure that the harness will not make contact with moving parts like the steering column, exhaust parts, and has sufficient slack between the engine and lines as well as lines and harness so that there is no strain as the engine moves.

  8. Power your car on but don't start it quite yet, go under the hood and check for leaks from the fuel lines.

  9. Flash an appropriate map for your modifications.

  10. Go out and enjoy!


Calibration Map Notes for Subaru Vehicles

Helps to figure out which map you should be on given the parts installed to your car 

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Email: support@cobbtuning.com

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