Gen 1: Secondary Air Injection System Bypass Kit (Wired)

(19 customer reviews)


The Gen 1 (V36W) is compatible with most 2005 – 2007 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 Block off Plate(s) and Starter Relay Wire.

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SKU: G1-36W Categories: , , Tags: , , ,


Hewitt Tech Generation 1 Secondary Air Injection System Bypass Kit (Wired)*
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. It is compatible with most Toyota and Lexus vehicles model years ’05 – ’07. The wired version of our Gen 1 bypass kit installs by tapping directly into the factory IAT/MAF Sensor harness. Easy to follow step by step installation instructions are included with wiring diagram and vehicle specific wire colors. The Gen 1 wired Bypass Kit is HT’s most affordable solution and will address the same error codes as the Gen 1 Plug & Play Bypass Kit. For those comfortable soldering wire connections and prefer a more discreet looking installation; this easy 6 wire hookup is for you.

It is Important to understand that HT SAIS Bypass kits are engineered to work with Factory or OEM SAIS components. That said, aftermarket SAIS components can cause fault codes to be present after installation of the bypass kit. This typically means you will need HT Kit Addon(s) in order to clear SAIS codes that are still present.

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

Mechanical Codes

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 – Wired In Connections
  • 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 wire in connections with wiring diagram.
    • 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


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!


*Professional installation is recommended. Wired kit installation requires splicing directly into the IAT/MAF Sensor factory wiring harness. For best connectivity, soldering wire connections is recommended.

**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.


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 .5 lbs
Dimensions 7 × 5 × 1 in

19 reviews for Gen 1: Secondary Air Injection System Bypass Kit (Wired)

  1. Dustan Hollifield

    I found out about Hewitt Tech after i had ordered the air pump and decided to give it them a shot. I really didn’t want to pull the intake and take the chance of messing something else up. I ordered the kit on Monday and received it on Thursday. I installed it the same day. My install time was about 35-40 min. As of right now i have not had any codes pop up or the vehicle go into limp mode but it jas only been a few days. Time will tell but it is looking like this was defiantly the correct choice.

  2. Ed B

    Your product did exactly as you contended it would. Used on my 2005 Toyota Sequoia due to an air pump issue (BS). Saved hundreds and passed ….without issue. Was a little more work than I thought it would be dealing with the tight confinements of the intake manifold but still very pleased.

  3. Paul Lie

    Incredible product. Installed in an evening just using basic tools. Instructions are detailed with pictures and diagrams.FedEx to me in 2 days. Saved me over $3000 in repairs at Toyota. Thanks so much.

  4. Sean W

    Got the check engine light out of no where one day about 5 mins after starting car . Was in limp mode (can’t go faster then slow) got the codes , googled and it’s the sec. air pump very common . I was just over 100,000 on my 2005gx. U can start car clear codes and it work until the next time you turn off long enough for engine to cool down. The parts to replace were expensive and a lot of work aka few hundred to have done or hours of work your self , shop non dealer even will tell u 700 . Got this by pass, installed in an hour and I’m still using today with zero problems it works 100%. You will forget it’s there , comes with directions

  5. Ryan

    This is crazy how awesome this company is awesome and I mean awesome customer service beyond 5 star if I could I would give 10 stars . I am a motor head and have been since I was young and after talking too customer care I honestly felt like I won the lotto !!!! This company is by fare the best out there in what they do!!!!! Thank you you guys rock !!!!!!!

  6. Wayne

    I just want to thank you for the Bypass Kit I purchased. I received it quickly, instruction were very clear and installed it myself with out any problems. My Tundra was 6 weeks pass the 10 year warranty with only 67000 miles, so Toyota would not cover it. I got a price to repair of $2100.00. Your kit works GREAT and saved me over $1900.00. Thanks, Wayne

  7. Jay Guthery

    Outstanding product. Instructions were spot on. Would highly suggest spending the six dollars for the penetration oil at your local auto parts store. Made the job so easy. Shipped quickly, even with the company shutting down for the 4th of July. From the time you receive the product, you can tell the company gives a crap about the customer. Packaged correctly and with care. Top-notch operation. The only complaint is they need to offer more products. With the quality of this kit, I would believe everything they sold would be perfect. Thank you!

  8. Bobby Tolleson

    Kit worked like a champ.No code or limp mode. A word about the install on bypass plates,on the 4.7 2007 tundra just loosen the 10mm nuts and slide the plates in.I took my off when it wasn’t required. It would’ve been easier to loosen. No big deal though.Great product!

  9. Chris Allen

    Ordered the wired kit for my 2005 Sequoia and it arrived in two days! If you have a solder iron this is an easy install. Pick up a 12 foot pack of 3/8 inch split wire loom from Home Depot for the starter wire.about $3. Perfect length to run along the fire wall. Left side plate was pretty easy to install from the top but right side has a bit less clearance and removing tire gives good access. Racheting 10mm combo wrench worked better than deep well socket on right side. Looking forward to fewer lights on the dash. Thanks.

  10. Brother_Bishop

    I bought my Tundra used from a good friend, and I knew about the AIP failure beforehand. I ordered the bypass kit but I don’t know anything about automotive work, so I had the kit for months before I had a buddy look at it and demystified the location of the valves. I’d been clearing the codes with a scanner and that was fine but it gets old. Finally installed the kit this weekend and drove around several different times and no codes! What a relief. My truck threw a CEL nearly every time I drove it and now it’s back to my old powerful beast again. You guys deserve a medal.

  11. Don WcWhirter

    Installed on my 2005 Toyota Tundra. Easy install at little over an hour. great product.

  12. Adam

    i installed this product on my 2012 Tacoma 4.0 and it worked flawlessly! The instructions were spot on and I loved the customer service that comes with this company. I would not hesitate to order through this company again. The install took a bit longer for me, almost 2 hours, because I have large hands and had to remove some extra parts to loosen bolts for the block off plates. So far no CEL and no limp mode for my truck!

  13. Michael

    We bought this for my father in laws 2006 LandCruiser and it worked perfectly. Paul was incredibly helpful and spent time on the phone with us on Sunday afternoon to knock it out. The directions are easy to follow and if you can change your oil I think you could tackle this job. The fact that you’re on this website instead of at the dealer spending $4K means you can tackle this job.

  14. Joe Boydstun

    Installed the kit in about an hour, super easy to install, and the system works great. The reader I purchase to clear the code was also amazing. Thanks for developing this fix, saved me lots of time and money. Thanks, Joe

  15. John Wise

    I bought this unit for my 05 tundra. Plugged it up and it worked great. Not to mention after ordering the unit it showed up the next day. Excellent service and a great product. Thanks

  16. Tim

    Ordered the module and it came in very quickly. I spent some extra time to make sure everything was well hidden because I still take the truck to the dealership for its regular service. I ended up making all the connections inside the main wiring harness just before it enters the fire wall and extending the wiring so I could mount the module on the passenger’s side kick panel inside the truck. I wasn’t about to pay the $2700 that the dealership quoted on fixing the system. I would recommend this module to anyone who is having issues instead of paying to fix the obviously flawed system.

  17. Dane

    Installed plug and play bypass on 2006 Tundra last night. Installed myself in about an hour. Works great better than spending 2K

  18. Jack Ashley

    I ordered your unit for my 2005 Sequoia on Monday after 12:00 had it the next day at 10am that’s great service & the unit worked like a charm THANKS for saving me a couple thousand dollars I don’t know what else you folks make but I rate this AAA Thanks Jack Ashley

  19. Tad


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