Frequently Asked Questions (FAQ):
(In no particular order of importance - if you don't see your question here give us a call)
The Secondary Air Injection System (SIAIS) is an emissions control system that is similar in operation to older smog pump systems. The SAIS is considered a secondary system because it is used to support the catalytic converters, a primary emissions system. It is an EPA mandated system and Toyota started equipping their vehicles with the system starting with the 2005 model year. Unlike older smog pump systems, the SAIS does not operate continuously and generally only operates for a short time during a cold soak warmup. This is the initial run cycle after the engine has been off for at least 7 hrs. The goal of the SAIS is to help get the catalytic converters reach operating temperature faster making them more efficient faster. This is done by leaning out the rich warmup exhaust and getting extra oxygen to the catalyst beds. There are various system configurations and components by year, vehicle and engine with the design slowly improving. On the Flex Fuel and all 2014 and newer model years this also includes the system operating momentarily at shutdown to eliminate water condensation from the system.
Limp mode (or "Limp Home Mode") is the fail-safe operation mode of a vehicle when there is a malfunction in one of the vehicle control systems. In limp mode, the computer will turn off systems like Vehicle Stability Control (VSC) and Traction Control (TRAC) for safety reasons. It will also put the engine into Open Loop Control, where the engine is running on baseline maps instead of relying on the sensors to tune its operation. This is where the lack of power and fuel economy comes from, when in limp mode. Limp mode can also affect how your transmission shifts. In limp mode, you are limited to about 50% throttle and no matter how hard you press the gas, you just won't go. For the SAIS limp mode is most often caused by the valve stuck open codes (P1441, P1444, P2440 or P2442). Limp mode is also indicated by the C1201 code if your vehicle has VSC/TRAC.
The Gen-II bypass kits are compatible with all aftermarket intakes and headers. The Gen-I bypass kits (V36/V54) are compatible with most aftermarket intakes, as long as the MAF/IAT sensor is in relatively the same location. We can make custom length units if needed for a small upcharge. Aftermarket headers are one of the applications for the bypass kits, even if you don't have a SAIS problem. On many applications, headers that include the Air Injection tube and exhaust port flange are not available or are priced very high compared to the headers without these features. With the bypass kit, you can install the headers without the air tube/flange to save money, but you may still need a header spacer plate to block off the Air Injection ports on the cylinder heads.
About 80% of the failures we see are caused by deterioration of the pump part of the air pump - this usually starts with the vacuum noise mentioned above. When this happens, the Air Injection Pump cannot create enough air pressure to push air into the exhaust when the Air Switching Valves open. Instead, the exhaust pulsations are allowed to reach the pressure sensor(s) in the system and trigger "Valve Stuck Open" codes. This is most often just the beginning stage of the SAIS failing. Most of the time, if it is just the pump starting to go out and cause the codes, you can clear the codes after the first start of the day when the system runs. If the codes stay cleared for the rest of the day and don't come back on until the next cold start, the cause is the failing Air Injection Pump. In this instance, just the standard bypass kit without add-ons would be able to take care of this for you. You will, however, want to get the bypass on there sooner rather than later because every time the system runs, the greater the chance of the failure progressing to something more expensive to take care of.
We are not talking about the actual intake and exhaust valves in your engine here, only the Air Switching Valves. Since this system is only connected to the exhaust, there is no real risk of actually damaging anything as far as the engine or transmission is concerned. The only risk of damage we have seen is to the Secondary Air Injection System's pressure sensor(s) when the valves are physically open or leaking exhaust. The 2007-2009 Tundra 4.7L and all 2010 and newer vehicles with the SAIS are more susceptible to sensor damage because of the closer proximity of the senor(s) to the hot-moisture laden exhaust gas.
When a pressure sensor is damaged it will usually only cause an inaccurate pressure reading and won't actually cause a pressure sensor circuit code. Typically, a damaged pressure sensor is the only way you can get a "Valve Stuck Open" code after installing the bypass kit AND block off plates. It is also why we see most of the pressure sensor correlation codes on the 2010 and later vehicles. You usually have a damaged pressure sensor if you can't clear a "Valve Stuck Open" code with the engine off, you have a pressure sensor circuit code or a pressure sensor correlation code. There are some nuances but we can usually determine if you need something like a pressure sensor harness or pressure sensor replacement kit addon ahead of time with some simple questions and tests. They can also be addressed afterwards but it is usually faster and easier if we can identify what you need first.
The short answer is usually yes. When a V36 or V54 kit is installed and all the codes are cleared the secondary air injection system's emission monitor will just show that the system is ready but not complete. It will never show complete because it is being tricked into not running. When a Gen-II kit is installed the system monitor will show that the system completed since we are emulating the system. So, as long as you don't have any other issues, have been able to clear all your trouble codes and have gone through enough drive cycles to set all the other emissions monitors you shouldn't have a problem. We do however only sell these for off-road or exempt vehicle use so we leave the decision to use our product completely up to the customer.
By itself, the bypass module does not have any effect on the performance or efficiency (gas mileage) of the vehicle. The module is only operational for a fraction of a second when the vehicle is started and does not alter anything long enough to affect things like fuel trims. It will, however, restore the vehicle back to normal power and gas mileage if you are stuck in limp mode.
The Gen-I bypass modules (V36/V54) are compatible with everything we have seen except those snake oil "performance chips" that install inline with the MAF/IAT. These interfere with how the modules operate and will need to be removed before installing the bypass kit. The Gen-II kits do not connect to or rely on anything except the computer and pressure sensors so there are no known compatibility issues.
This is a really common question, mostly because the plate installation can seem a little daunting. However, the block off plates are an integral part of the solution. In cases where the actual Air Switching Valves are physically stuck open or leaking the block-off plates are 100% required. In other instances, where the problem is just a failing Air Pump causing the problems, they are not as imperative but the best practice is to always install them at the same time as the bypass module. This is because even though the system is not running anymore, the Air Switching Valves have been known to leak further down the road and put you into limp mode. The only way to completely isolate the system from exhaust and ensure that the system is not a problem again is to install the block off plates. If you don't install them, we recommend to at least put them in your glove box so you know where they are if/when you need them.
On all of the 2005-2009 4.7L engines, there is one Air Injection Pump located under the intake manifold, while the 2007-2009 4.7L and 08-09 Sequoia 4.7L Tundra has an additional pump in the front passenger side fender. All 5.7L engines have a pair of Air Injection Pumps located in the front passenger side fender. The 4.6L engines have one Air Injection Pump located in the front passenger fender. The 2.7L and 4.0L engines have the Air Injection Pump located in the engine compartment, usually on the inner passenger side fender at the front or back.
The Gen-II kit is the only one for you. The Flex Fuel version of the 5.7L V8 (3UR-FBE) will run the Air Injection Pumps on engine shutdown, while some other engines do not. However, the Gen-I kits (V36/V54) can only prevent the system from running on startup. For this reason, the Gen-II is the only solution for any vehicle that runs the Air Injection Pumps at shutdown, including all 2014 and newer vehicles.
The Gen-II kits will work on all vehicles regardless of a reflash. There is only one possible reflash of the ECM that we are aware that would make a vehicle incompatible with the V54H kit. There was a Limited Service Campaign for certain 2012-2013 5.7L Tundras and Sequoias that were getting P2441, P2443 in freezing ambient temperatures. This LSC involved a reflash of the ECM that causes the Air Injection Pumps to run on engine shutdown like the Flex Fuel vehicles do to eliminate moisture from the valves. If you have a 2012 or 2013 5.7L Tundra or Sequoia that has been reflashed with this calibration file, there should be Toyota Modification Sticker on the underside of the hood with the new calibration file (however, they are rarely applied). If there is any concern your vehicle has been reflashed, we recommend installing a Gen-II kit to avoid any confusion.