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Subaru CAN Gateway Flex Fuel Kit

Subaru WRX MT 2015-2021

Congratulations on your purchase of the COBB Tuning CAN Gateway 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.

Parts List

343650 / 344650 Gateway Harness/Bracket

Vehicle Harness (Difference Between Kits

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344650 - 2018-2021 WRX (Brown)

These are denoted by the presence of the power steering control module on the passenger’s side frame rail on the older vehicles.

Gateway Bracket (VA)

 

(2) M6 x 1.0 x 14mm Button Head Allen Screw

 

M8x1.25 Serrated Nut

 

M8x1.25x16mm flanged hex bolt

 

 

344750 - CAN Fuel Pressure Sensor

Thread Sealant packet

Tools Needed

Sockets

3/8"

• 3/8" ratchet

• 3/8" 12" extension

• 3/8" 6" extension

• 3/8" 10mm deep socket

• 3/8" 12mm deep socket

 

Misc.

• Subaru Fuel Line Disconnect Tool (Not Subaru specific but a size appropriate for a Subaru)

• 22mm wrench (For fuel pressure sensor)

Stock component removal

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

2. Discharge the existing fuel pressure from the system. Consult the factory service manual for OEM methods. One potential method is to disable the fuel pump by pulling the fuse on the driver's side of the engine bay (consult the underside of the lid for correct fuse location), then attempt to start the vehicle. The vehicle will likely run for a brief moment and stall. Fuel pressure is reduced by this method, but some pressure may remain in the system. (I recommend doing this with the car colder, it may add some heat to the engine bay, however with the engine hot, any fuel that gets on the exhaust is a fire risk.
   
   

   
   
   

3. Once the vehicle stalls out due to loss of fuel pressure, turn it off and allow it to cool down. Feel free to hang out with friends.
   
   

   
   
   

4. Using a 10mm disconnect the negative terminal of the battery followed by the positive terminal. Disconnecting the positive first can still cause things to be active as touching the connector to ground anywhere will allow it to connect. However disconnecting the ground first, means the chassis is no longer an integrated part of the electrical system and therefore the safer option.
   
   
   

5. Using your deep 1-mm or a wrench and some perserverence, undo the battery tie down, then remove the battery from the car.
   
   
   

6. Still with the 10mm, loosen the two bolts on the top of the fuse box.
   
   
   

7. Now remove the bolt on the bottom.
   
   
   

8. Moving on to the next section, use your fuel line disconnect tool to release the stock fuel line from the fuel rail near the intake manifold, as well as where it attached to the firewall. Once you remove one end some fuel may come out, so shielding it with a paper towl or similar is advisable.

Fuel Pressure Sensor Pre-Assembly

1. Put a dab of the provided thread sealer on the threads to the fuel pressure sensor and thread it into the quick connect adapter carefully.
   
   
   

   
   
   

2. Using a 22mm wrench tighten it to 7 ft-lbs. It shouldn’t thread down all the way as these are tapered threads.
   
   

Ethanol Content Sensor Installation

1. Install the fuel lines to the ethanol content sensor. The shorter of the two will go on the sensor side with the connector. Make sure the connector is fully pushed on to the barb before closing so that it is retained over the raised portion
   
   

   
   
   

   
   
   

2. Orient the bracket so the fuel connections are on the top, and the electrical connection on the bottom, facing the engine. Use the smaller hole closest to the sensor so that the sensor doesn't hit the metal cover on the engine
   
   

   
   
   

3. The longer side should make it over to the firewall where you removed the fuel line earlier.
   
   

   
   
   

4. First snap the fuel pressure sensor adapter onto the fuel line coming out of the intake manifold, then the shorter fuel line from the ethanl content sensor will attach to that. Make sure to snap the blue or white collar down to hold the fuel line in place. If installed properly, it shouldn’t easily pull off and will be easy to rotate freely. If installing the fuel pressure sensor, it will go between the engine side and this fuel line.
   
   

    

    

Gateway Module Installation

1. Install the gateway module to the bracket using the provided allen bolts.
   
   

    

   
   
   

2. On the passenger’s side strut tower behind the ABS system, locate a stud and open threaded hole (you may need to remove a sticker over it) Slip the open slot side of the bracket over the stud and rotate it down.
   
   
   
   
   

3. Using the provided bolt and nut, attach the bracket to the strut tower, then tighten the nut on the other side.
   
   

    

Relocated CAN Gateway Bracket (Optional)

Gateway Harness Installation

1. Use the included bolt to attach the ground eyelet to the strut tower. There maybe a sticker covering the threaded hole.
   
   

   
   
   

2. With the ground attached and the vehicle side of the harness plugged in you can route the harness over and around to the top left Vehicle port of the gateway. I prefer to go under the abs module for a cleaner routing.
   
   

    

    

3. Zip tie the harness to the existing engine harness in that area to keep it out of the way of moving parts.
   
   

   
   
   

4. The harness can get plugged into the top left vehicle port of the gateway. The connectors are keyed and only fit in one way, gently spin the plug until it slides into place, then tighten the screw by hand. The connector only needs to be screwed down snug, it will most likely not be all the way down against the gateway.
   
   

    

    

   
   
   

5. Run the ethanol content sensor across the firewall along the brake and ac lines and over to the ethanol content sensor. Make sure it isn’t overly tight or hitting anything that needs to move. This step can be much easier if you take a few minutes and just remove the intercooler.
   
   

   
   
   

6. Once routed, secure it with zip ties a few times along the way, and plug it into the ethanol content sensor and Gateway respectively. It can get plugged into either of the bottom ports of the gateway, they are self identifying harnesses so the module will detect which sensor is where.
   
   

   
   
   

7. Route the fuel pressure sensor in a similar fashion either along the firewall, or under the engine cover/intake manifold to plug into the fuel pressure sensor. Make sure to connect the sensor all the way until the tab clicks into place
   
   

    

    

    

Final Prep and Reassembly

1. With everything plugged in, re-install your battery. (Make sure to wait until any fuel you spilt has dried before reconnecting to avoid a fire.)
   
   

2. Reinstall the fuse for the fuel pump.
   
   
   

3. Once the battery and fuse are reinstalled key the car on and then off again (without starting). After this cycle look over your fuel lines for any leaks. Repeat this process 3-4 times.
   
   
   

4. Once you’re happy with the fuel line situation, go ahead and start up the car. You’re all done!

CARB Sticker Application

(Where Applicable)

1. Apply the supplied CARB sticker in a clear, easy to find location.  Typically underhood, or on the radiator core support.

Links

MAP Notes

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

Links for related parts