Frequently Asked Questions (FAQ):
(In no particular order of importance, if you don't see it here give us a call)
1) What is "limp mode"?
Limp mode comes from the terminology of "Limp Home Mode". It 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 come 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.
2) What is the vacuum cleaner or loud electric motor sound I hear when I first crank the engine?
If it is the secondary air injection system (SAIS) pump, the sound will typically only last for 30-45 seconds on a cold start and then stop. The noise you are hearing is usually the air pump vanes grinding against the pump body or the bearings in the pump motor going bad.
For most people this is the first sign of trouble with the SAIS system. You may not have trouble codes at first but for most people it only takes a few times of hearing that noise before the trouble starts.
There is no real way of knowing how ling it will do that before total failure. Some people never hear the noise but for most it is at most a week before the pump motor gives up the ghost and causes a P0418 or P0419 code.
If you are hearing this noise it is best to bypass the system as soon as possible to prevent it from completely failing and causing a more expensive repair than the bypass kit alone can take care of. We do have pump replacement
packs if it gets that far.
3) Can the SIAS components be removed after installing a bypass kit?
With the current bypass kits, not exactly. Disconnecting any of the electrical components even with the bypass kit installed will cause trouble codes and set the CEL.
We do have kit addons which are proxies or tricks for most of the components that would let you remove the original part but these are usually only used if the original part is causing a circuit trouble code.
An example would be a bad pump motor (P0418/P0419), you would add a pump replacement pack (PRP) to take care of the code and since you are disconnecting the original part to install the PRP you can remove the old pump.
However, unless you are building a custom truck or need the room where the original pump is most people just opt to leave the bad pump in place. We can do the same for the solenoid type air switching valves and pressure sensors.
Check out the Kit Addons.
4) Will the bypass kit work with aftermarket intakes/headers?
The bypass kits 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 up charge.
Aftermarket headers are one of the applications for the bypass kit 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 saving money but you may still need a header
spacer plate to block off the air injection ports on the cylinder heads.
5) How can I tell if my air pump is failing or causing my trouble codes?
About 80% of the failures we see are caused by deterioration of the pump part of the air pump, this usually starts with the noise mentioned in #2 above. When this happens the air 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 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 the the failing air pump. In this instance just the standard bypass kit without addons would be able to take care of this for you. You will however want to get the
bypass on there sooner than later because every time the system runs the greater the chance of the failure progressing to something more expensive to take care of.
6) Can Valve Stuck Open or Closed Codes a stuck open valve damage my engine?
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 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.
7) What does a damaged pressure sensor mean?
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.
8) If the system is bypassed can I pass an emissions test?
The short answer is usually yes. After installing the bypass kit and clearing everything the secondary air injection system's emission monitor will just show that the system is ready. It will never show complete because it is being tricked into not running.
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.
9) Does bypassing the system have any effect on engine performance?
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.
10) Is the kit compatible with super/turbo chargers, performance "chips" and remote starters?
The bypass modules 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.
11) Can I install the bypass module without the block-off plates?
This is a really common question mostly because the plate installation can seem a little daunting but the block off plates are an integral part of the solution. Many times the problem is just the air
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 immediately required 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 the exhaust and ensure that the system is not a problem again is to install the block off
plates. Just install them and don't worry about it again. If you don't make sure you put them in your glove box so you know where they are if and when you need them.
12) Where are my Air Injection Pumps located?
On all of the 2005-2009 4.7L engines there is one pump located under the intake manifold while the 2007-2009 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 pump located in the engine compartment usually on the inner
passenger side fender at the front or back.
13) What does p0418 and/or P0419 mean?
These two codes read as relay circuit malfunctions but 99.9% of the time it means that your air pump(s) are out of spec. Most often this is because the pump has burnt itself out as an open circuit.
With the bypass kit installed we don't need a functioning air pump motor but only something to make the air injection control driver think the pump is OK. This is where our Pump Replacement Packs come into play since
the bypass module by itself cannot clear these codes.
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