Secondary Air Bypass Kit Comparison

Hewitt Technologies Secondary Air Bypass Kit Comparison Gen 1 vs Gen 2

Hewitt Tech Bypass Kits come in two Generations, Gen 1 and Gen 2. When deciding which kit is best for you please note that our solutions are both vehicle specific and error code specific. That said, compatibility depends on the Year/Model/Engine Size of your vehicle. Additionally, the error codes that are present will play a factor in bypass kit selection and will help determine if you need any Kit Addons.

It is also important to understand the Gen 1 and Gen 2 Bypass Kits operate differently and as a result will address different subsets of SAIS fault codes. Please also be aware that installation will vary according to engine size and bypass kit selected. After reading this article, we encourage you to use the Search By Vehicle feature on our site to find compatible bypass kits. Individual product listings will provide further details.

Gen 2 Bypass Kits

The Gen 2 is Hewitt Technologies most comprehensive Bypass and the best solution to address or prevent Secondary Air Injection System failures. Unlike the Gen 1 Bypass Kits which only manipulates the operation of the SAIS, the Gen 2 Bypass Kit fully emulates it. Why is this an advantage? First, the Gen 2 can address both Mechanical and Electrical SAIS fault codes. This limits the potential need of kit addons in the future. Second, the Gen 2 is compatible with Toyota’s most recent ECM flashes and recalibrations. This includes ECM programming for Flex Fuel models. Lastly, since the Gen 2 is emulating the SAIS system this means monitors will show as ready and complete. Gen 2 Bypass Kits will include Block Off Plates to prevent future damage of pressure sensors by exhaust.

There are two variations of the Gen 2 Bypass Kits.

Gen 2 (Plug & Play)

Compatibility: Most Toyota and Lexus vehicles model years ’05 – Current

The Plug & Play version of the Gen 2 Bypass Kit offers a complete Plug & Play installation with connectors compatible with the vehicle’s factory components. The Bypass harness connects to the Air Injection Drivers (AID) and Air Switching Valves as well as the factory harness. The Gen 2 (Plug & Play) Bypass is Hewitt Technologies most recommended solution because of its ease of installation and offers the most comprehensive SAIS code coverage.

Gen 2 (3 Valve)

Compatibility: Select Toyota and Lexus 4.7L vehicles model years ’05 – ’09

The 3 Valve version of the Gen 2 Bypass kit is for specific vehicles with 4.7L engines. On these vehicles the entire SIAS is located underneath the manifold. The 3 Valve kit will provide the same code coverage as the Plug & Play version. However, installation of the Gen 2 (3 Valve) Bypass is Plug & Play as well as Wired. The Plug & Play portion of the harness connects to the AID and Vacuum Switching Valve (VSV) factory harness. The Wired portion is ran through the fire wall and tapped into the factory harness at the ECM. If you are not comfortable with soldering or tapping into the factory harness at the ECM, we recommend professional installation.

Gen 1 Bypass Kits

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 Gen 1 Bypass Kit is compatible with most Toyota and Lexus vehicles model years ’05 – ’12 and select ’13, ’14 vehicles. It is made with automotive grade materials and designed to blend in with the factory wiring harness. Bypass kit will include Module, Harness, Block off Plate(s) and Starter Relay Wire. The starter relay wire is a feature only available from Hewitt Technologies and when connected, ensures that the module actively prevents the SAIS from running on EVERY start. Gen 1 Bypass Kits are NOT compatible with Flex Fuel models or vehicles with certain ECM reflashes.

There are two variations of the Gen 1 Bypass Kits.

Gen 1 (V36H)

Compatibility: Most Toyota and Lexus vehicles model years ’05 – ’07

The Gen 1 (V36H) is a product of Hewitt Technologies Original SAIS Bypass Kit. This design gave the first viable alternative to expensive repairs for Toyota/Lexus owners to address the failure prone SAIS. The Gen 1 (V36H) is tried and true being installed on thousands of vehicles since 2014. Without a doubt one of our most popular solution because its ease of installation and very competitive price point.

Gen 1 (V54H)

Compatibility: Most Toyota and Lexus vehicles model years ’08 – ’12 and select ’13 vehicles

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 requiring 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 to 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.

Which Bypass Kit is Right For You?

There are a few factors that will help you decide the best solution for your vehicle. As mentioned above, Year/Model/Engine Size will determine which Bypass Kit your vehicle is compatible with.  Next, you will need to know the error codes. If you are only tripping Mechanical codes then the Gen 1 Bypass Kit maybe a good option. However, if your codes are Electrical, Gen 1 Bypass requires Kit Addons in addition to the Bypass to address. In this case Gen 2 would be a better rout because it will cover both Mechanical and Electrical error codes.

You will also want to take installation into account. Bypass Kits which are Plug & Play include Gen 1 (V36H), Gen 1 (V54H) and Gen 2 (Plug & Play). Plug & Play Bypass Kits were designed with the DIY mechanic in mind, they are installed using only basic tools and no technical knowledge or skill is needed. We say if you can change your oil and change your tires; you can install these kits. Hewitt Technologies also offers a few Bypass Kits that requires tapping wires into the factory harness. This includes the Gen 1 (V36W) and Gen 2 (3 Valve). Installation of these Bypass Kits are a little more involved. Therefore, if you are not comfortable with soldering or tapping into the factory harness, we recommend professional installation.

In conclusion, the Hewitt Tech recommended solution is the Gen 2 Bypass Kit. As described above, it is the most comprehensive and advanced Bypass Kit. If you want to get out of Limp Mode, turn off your Check Engine Light, avoid future failures and save thousands of dollars; Gen 2 is what you are looking for.

What do my Secondary Air Injections Error Codes Mean?

To learn more about the different types of SAIS fault codes and more details about specific error codes, read our Blog post What Do My Error Codes Mean?

What is the Secondary Air Injection System?

To learn more about purpose and components of the Secondary Air Injection System, read our Blog post What is the Secondary Air Injection System?

Contact Us

If you have any questions about compatibility or which solution is best for you do not hesitate to contact us. You can reach Customer Service and Technical Support at (844) 307-7671 Monday thru Friday 8:30am – 5:00pm ET. Or feel free to send us a message through our Contact Us page. Hewitt is here to help.

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