Gen 1: Secondary Air Injection System Bypass Kit (Plug & Play)

(41 customer reviews)


The Gen 1 (V54H) is compatible with most 2008 – 2013 models. It is our basic bypass kit that enables you to clear the Check Engine Light, Limp Mode and error codes related to mechanical SAIS faults. Bypass kit will include Plug & Play Harness, Block off Plate(s) and Starter Relay Wire. (NOT COMPATIBLE with Flex Fuel vehicles)

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Hewitt Tech Generation 1 Secondary Air Injection System Bypass Kit (Plug & Play)
The Hewitt Tech (HT) Gen 1 Bypass Kit prevents operation of the SAIS at cold soak start. The Gen 1 is our basic bypass kit that enables you to clear the Check Engine Light, Limp Mode and error codes related to mechanical SAIS faults. The V54H is compatible with most Toyota and Lexus vehicles model years ’08 – ’12 and select ’13 vehicles. However, it is not compatible with Flex Fuel vehicles. Like the V36H, the V54H Plug & Play Gen 1 Bypass kit decreases labor/Install time with connectors compatible with the vehicle’s factory components. All wiring connections, except the starter relay wire, are achieved using the Plug & Play harness. It is made with automotive grade materials and designed to blend in with the factory wiring harness. This allows for a very clean factory looking installation. Easy to follow step by step installation instructions are included with vehicle specific illustrations. We recommend the Gen 1 Plug & Play Bypass kit for both professionals and DIY mechanics because of the ease of install and affordability. However, if the vehicles ECM has been flashed with an updated calibration file the Gen 1 may not be compatible. If the vehicle has been reflashed then you will need to purchase the Gen 2 Bypass Kit. Please see note below of for additional information*.

The following are Mechanical Trouble codes the Gen 1 Bypass Kit typically addresses**:

P1441 – Switching Valve No.2 Stuck Open Bank 1
P1442 – Switching Valve No.2 Stuck Close Bank 1
P1444 – Switching Valve No.2 Stuck Open Bank 2
P1445 – Switching Valve No.2 Stuck Close Bank 2
P2440 – Switching Valve Stuck Open Bank 1
P2441 – Switching Valve Stuck Closed Bank 1
P2442 – Switching Valve Stuck Open Bank 2
P2443 – Switching Valve Stuck Closed Bank 2
P2445 – Pump Stuck OFF Bank 1***
P2447 – Pump Stuck Off Bank 2

The following are Trouble codes NOT addressed by the Gen 1 Bypass. These will require kit addon(s) in order to clear. However, if you are getting any electrical codes our recommended solution is the Gen 2 Bypass kit.

Electrical Codes

P0412 – SAIS Switching Valve ‘A’ Circuit Malfunction Bank 1
P0415 – SAIS Switching Valve ‘B’ Circuit Malfunction Bank 2
P0418 – SAIS Circuit/Relay ‘A’ Circuit Malfunction Bank 1
P0419 – SAIS Circuit/Relay ‘B’ Circuit Malfunction Bank 2

Electrical SAIS error codes are usually caused by an open or short circuit in one of the Air Switching Valves or Air Pumps. Each code would require a separate addon.

Pressure Sensor Codes

P2431 – Air Flow / Pressure Sensor Circuit Range / Performance Bank1
P2432 – Air Flow / Pressure Sensor Circuit Low Bank 1
P2433 – Air Flow / Pressure Sensor Circuit High Bank 1
P2436 – Air Flow / Pressure Sensor Circuit Range / Performance Bank 2
P2437 – Air Flow / Pressure Sensor Circuit Low Bank 2
P2438 – Air Flow / Pressure Sensor Circuit High Bank 2
P106B – Pressure Sensor Correlation / Evap. Pressure Sensor

These codes typically indicate a damaged Pressure Sensor which is usually caused by an Air Switching Valve being stuck open for an extended period of time. Functioning Pressure Sensors are needed for both Gen 1 and Gen 2 Bypass kits. Compatible Pressure Sensor addon required in order to clear.


  • 1 x SAIS Bypass Module – Plug & Play Connections (IAT & ECT)
  • 2 x Secondary Exhaust Valve Block Off Plates (Engine Specific)
  • 1 x 10′ Piece of Violet 20 AWG TXL – Starter Relay Connection Wire
  • 1 x Printed Copy – Detailed Bypass Module Installation Instructions
  • 1 x Printed Copy – Block Off Plate Instructions (Engine Specific)


  • Bypass Wiring Harness:
    • Straight forward Plug & Play connections compatible with Factory components.
    • High Quality Automotive Engine Compartment Grade TXL Wiring
  • Bypass Module:
    • 4cm x 4cm x 1.4cm Black Duroplastic High Temp Enclosure – UL 94 V-0 Flame Resistance
    • Black Epoxy Potted for environmental and shock protection.
  • Block Off Plates:
    • 16 gauge (1/16 inch) 316 Stainless Steel Block Off Plate Construction for Lifetime Use
    • Water Jet Cut for Precision and Smoother Edges, Guaranteed to Fit Your Engine
  • Start Relay Wire:
    • ONLY available from Hewitt Technologies home of The Original SAIS Bypass Modules.
    • 10′ Piece of Violet 20 AWG TXL wire with female disconnect terminal.
  • 3M™ Automotive Acrylic Double-Sided Tape for mounting
  • Assembled 100% by hand in the USA!
  • Limited Life-Time Warranty


What makes the Gen 1 (V54) Bypass Kit different than the Gen 1 (V36) Bypass Kit? In 2008 there was an update made to the computer programming that affected SAIS operations. With this change a new module had to be engineered with two harnesses; installing at both the Air Intake Temperature (IAT) sensor and the Engine Coolant Temperature (ECT) sensor. Our competitors have not taken this update into consideration with their products. That said, if you were install a competitor’s kit or Gen 1 (V36) on a model year ’08 or newer, you would get the error code P011B – Temperature Correlation Error. Just another reason to go with HT, the original SAIS bypass. Lastly, we have seen an intermittent chocking start issues on some vehicles using the Gen 1 (V54) ****.

The bypass module is activated when the ignition is first switched to “ON” and any time it detects a 4-12V signal on the starter relay wire. The starter relay wire is only available from Hewitt Technologies home of the Original SAIS Bypass Modules! When connected, ensures that the module actively prevents the SAIS from running on EVERY start.

With the starter relay wire connected you can turn the ignition to “ON” for any period of time and the module will be active as soon as you crank the engine. Without the starter relay wire connection, you would need to turn the ignition back “Off” and then crank the vehicle to ensure the module is active or the system could operate and cause trouble codes and the CEL to come back on. Just install the kit with the starter relay wire connection and don’t worry about having to start the engine as soon as you turn the key on! If anyone else drives the vehicle this is a Must!

The included Air Switching Valve Block-off Plates are an integral part of the bypass kit. The Block Off Plates are the only way to isolate the Air Switching Valves and protect the related Pressure Sensor(s) from damage caused by exhaust. Open Air Switching Valves and Pressure Sensors exposed to exhaust are the primary cause of Limp Mode and SAIS failure.

It is important to understand that installing a HT bypass will prevent your Air Pumps and Air Switching Valves from operating. However, it will not close the Air Switching Valves or keep them closed in the future. That said, choosing not to install the Block Off Plates leaves the SAIS vulnerable because exhaust may leak into open valves and damage the Pressure Sensors. As noted above, both Gen 1 & 2 HT bypass kits require kit addons to clear SIAS Pressure Sensor codes. Do yourself a favor, avoid future frustrations and costs; install the Block Off Plates.

If you are having a hard time determining which is the best solution for your vehicle, please do not hesitate to give us a call or send an email. Hewitt is here to help!


*Gen 1 Bypass Kits are not compatible with vehicles that have had the ECM updated with a calibration file from Toyota Technical Service Bulletin T-SB-0033-12. It is assumed that this ECM update will cause the secondary air system to operate at shutdown after the vehicle has reached operating temperature. Only Gen 2 Bypass can prevent SAIS system operating at shutdown. Click Here to Learn more.

**The vehicles fuses, Pressure Senor(s), factory wiring harness and Engine Control Module (ECM) must be in good working condition for bypass kit to operate properly.

***There is a known “Cold Weather Glitch” on some older 4.7L engines. If the vehicle is tripping a P2445 and it is caused by this glitch; the Hewitt Technologies SAIS Bypass Kit will not resolve the issues. Please visit our Error Codes page or give us a call to learn more.

****There is a known intermittent chocking start issue on vehicles that our more sensitive to after installing Gen 1 (V54) Bypass Kit. This is due to the tolerance in the engine temperature sensor. It most commonly occurs when the engine temperature is between 90 – 100 degrees.

+HT SAIS Bypass kits are engineered to work with Factory or OEM SAIS components. That said, aftermarket SAIS components can cause SAIS codes to be present after installation of the bypass kit. This typically means you will need a kit addon from Hewitt Tech in order to clear SAIS codes that are still present.


It is illegal to remove, dismantle or otherwise cause to be inoperative any pollution control device required by federal, state, or local emissions law. Our bypass kits are sold for off-road, competition or other emissions exempt vehicles only. No other applications are intended or implied. By installing or using this SAIS Bypass Kit the vehicle owner and installer acknowledge and assumes ALL risks associated with its use.

Additional information

Weight .8 lbs
Dimensions 8 × 6 × 1.5 in

41 reviews for Gen 1: Secondary Air Injection System Bypass Kit (Plug & Play)

  1. Tom L

    Was having problems with my secondary air injection pump. 2010 tundra with 97000 miles. Took a gamble and installed hewitt kit. Took about 1 1/2 hours.
    Been 5000 miles and no problems. Don’t go to dealer, ho to hewitt technologies. Thank you folks! Awesome product

  2. Richard Pinkerton

    I was out on a job when Toyota’s infamous Secondary Air Injection system began to fail. Like a fool I figured I’d try complying with smog requirements and after $266.00 in new pumps and hoses, realized that I had made a grievous mistake.we don’t have those smog requirements in my state! Good, but the new pumps weren’t working anyway. So I went all in on Hewitt’s bypass system. Best damn move yet! Runs like a champ! Fuel mileage is at 15.9 mpg running the mountains and cities in Oregon. Prarie running at 18.2 mpg.
    Thank you Claire, Steve and all at Hewitt Technology!

  3. Danny

    All I can say is awesome awesome awesome awesome! Bypass kit is installed, truck is running like a scalded dog! And 1st rate customer service! Email responded to on a Sunday when I had a question on the install.Thank you so much for saving me alot of money!I would put this on an older tundra EVEN IF the codes weren’t up!

  4. Brad

    2012 Toyota Tundra. Waited a month before writing a review. I couldn%u2019t be happier about the results. Installation took me about 1.5 hours. The hardest part was installing the blockers on the pump that was harder to reach. Thanks for offering this product and saving us $2600!

  5. Josh Meadows

    I know I wish I woulda purchased it. I was thinking it was covered in the recall on my 2012 tundra but Toyota said the 4.6 wwasnt on the recall just 5.7

  6. Wes Waters

    I installed this device with a bit of skeptisisim but I was pleasantly supprised. The dealership turned me down on replacing my secondary air injection system saying I had too many miles on my truck to be covered by the warantee. So I looked at this as my only option that was financially available. One thing I have noticed is that it does seem to be a little harder to start after some small trips than it was before. Almost like it needs some gas and is not getting it soon enough. It didnt do that prior to the install of this device. As far as error codes go. All gone and the traction controll is back working now. Toyota now sent me a letter saying they would cover the secondary air injection device up to 150k miles but if you got that letter dont count on it. I took this device back off took my truck to the dealership they then told me it doesnt match the exact code needed to get the free replacement and wanted to charge me $50 for evaluating my truck. I wouldnt pay and brought my truck home and put the device back on. Better to just keep this fix and be happy.It works.

  7. Jim Farmer

    Just installed today on a 2008 Tundra 4.7L to resolve a P2443 code.The kit worked wonderfully. The install was simple. The instructions that came with the kit were fantastic.The total install time was about 45 minutes. Nothing about this was difficult.Thank you, Hewitt!

  8. Justin Gerret McConnell-luer

    If your mechanically inclined, it only takes a couple hours. Hardest part is the block off plates.

  9. Andrew

    Toyota would not honor the warranty to replace the SAIS in my 2012 Tacoma 4.0L because it was Rebuilt, and wanted over $2k to fix it. I could have ordered the part and replaced it myself probably, but it still was going to be over $500, and this was going to be the first time fixing something with the engine myself. AND I read reviews that part goes bad every 10k miles or so in Tacomas because of bad design, so I decided to take my chances with the SAIS Bypass kit instead.

  10. Jason

    2008 Tundra 5.7L was in limp mode due to CEL being on code P2445 I found water in air injection pump regulator on bank 1 and had corrosion in the valve assembly so would obviously need new valve and air pump which was around $1200 cost in parts alone. My neighbor is a great mechanic and spoke to several other mechanics and they all recommended this option from Hewitt. It took about an hour to install with no issues. Instructions are great with excellent tips on installing the exhaust blank offs. I’ve only driven it 4x since installing but so far no codes and typically it would come on again after two runs before by clearing the CEL so far it’s doing what’s it’s supposed to do. Thanks for what looks like a great way to go.

  11. Lam T

    I ordered the Plug & Play SAIS Bypass Kit for my 2008 Tundra 5.7 on Thursday and paid for overnight shipping. It was delivered on Friday and it took me about 2 hours to install it. I watched the install videos that Hewitt-tech posted on youtube and it really helped. No more limp mode and all CEL are gone. I took a 200 mile round trip after the install and still no CEL. This product works.

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