Error codes, or diagnostic trouble codes (DTCs), consist of alphanumeric characters that correspond to specific issues with a vehicle. When a DTC is tripped, the check engine light (CEL) will appear on the dash. Once a CEL appears, it is important to use an OBDII scanner or another scan tool to read the DTCs. If you do not have access to an OBDII scanner, you can find one to use free of charge at most local auto parts stores.
If you are looking to purchase a scan tool, Hewitt Tech sells a variety of scanners from iCarsoft with features ranging from reading and clearing codes to accessing and live stream and freeze frame data. Click Here to view.
There are many reasons why it’s essential to know the vehicle error codes, but the most important reason is being able to identify and troubleshoot issues. Secondly, our bypass kits are vehicle and error code specific. We will confidently provide you with the best solution after you provide us with the specific DTCs and the year, model, and engine of your vehicle.
Types of Secondary Air Injection Failures and Error Codes
There is a limited set of DTCs the secondary air injection system can trip. We have categorized them into three types of failures: mechanical, electrical, and pressure sensor. This is important to note because Hewitt Tech bypass kits only cover certain codes, and kit add-ons may be required to address other SAIS codes.
Please know that neglecting SAIS error codes, repeatedly clearing them, and driving your vehicle can lead to further damage. This includes damage to the factory wiring harness or the engine control module (ECM). The Hewitt Tech bypass kit will not address this damage.
Listed below are the most common SAIS error codes that can typically be addressed by the Hewitt Tech bypass kit or bypass kit with an add-on. To confirm code coverage, please refer to Bypass Kit Comparison Chart or specific product listing.
Mechanical codes relate to the moving components of the SAIS. For example, if the air pump fan is malfunctioning or the air switching valve is stuck, one of the following codes will appear:
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
Electrical codes indicate an issue with the circuit within the SAIS components. Each air pump and air switching valve has an electrical circuit. The following codes are usually caused by an open or short in these circuits:
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
Pressure Sensor Codes*
The following codes are directly associated with damaged pressure sensor(s). This is commonly caused by an air switching valve being stuck open, which exposes the pressure sensor to exhaust. The following codes will put the vehicle into “limp mode” and will not clear until addressed:
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
What Causes the Secondary Air Injection System to Fail?
It’s no secret that secondary air injection systems on Toyota and Lexus vehicles are prone to failure. As detailed above, the primary reasons for error codes are mechanical, electrical, or pressure sensor faults. Many factors contribute to these failures, including moisture entering the system, air pump debris, carbon buildup, and general wear and tear.
Other Reasons SAIS Codes Are Tripped
As discussed above, the primary reasons for SAIS error codes are mechanical, electrical, or pressure sensor failures. However, there are a few other causes that can trip SAIS DTCs. One of the most common is damage to the factory wiring harness that is plugged in to SAIS components. We have seen everything from broken wires to wires with damage from rodents trip SAIS error codes.
If not addressed in a timely manner, incorrect voltage or resistance across the factory wiring harness can damage the ECM. Again, the factory wiring harness and ECM must be in good working condition for the Hewitt Tech bypass kit to work properly. The bypass kit will not address SAIS codes caused by damage to the factory harness or ECM.
Another factor that frequently causes SAIS error codes is aftermarket SAIS components. These components are not made with the same high-quality material used in factory parts or original equipment manufacturers (OEM) parts. Aftermarket parts may be cheaper, but they will most likely cost you more in the long run. If you are considering replacing SAIS components, use factory or OEM parts.
However, replacing the secondary air injection system can cost $2,000 to $3,000. Even if you decide to replace these components, you would likely run into the same issues in the future. So, if you want to get out of “limp mode”, turn off your check engine light, avoid future failures, and save thousands of dollars, you need a Hewitt Tech secondary air injection bypass kit.
Other Common Codes
The Hewitt Tech bypass kit and kit add-ons are engineered to address a specific set of error codes related to the SAIS. Please understand that our solutions do not clear codes associated with a vehicle’s other systems. You can view a list of other common codes for reference on our website’s Codes page.
We strongly recommend addressing codes not related to the SAIS before installing a Hewitt Tech bypass kit. This limits potential troubleshooting issues and allows vehicles to complete tests after installation. There have been instances where SAIS codes would not clear until other codes were directly addressed.
Additional Secondary Air Injection Resources
To learn more about the Hewitt Tech bypass kits, as well as the purpose and components of the secondary air injection system, click on the following “Must Read” Hewitt Tech blogs.
Have questions about your codes or our solutions? Call Customer Service and Technical Support at (844) 307-7671, Monday through Friday from 8:30 a.m. to 5:00 p.m. You may also send us a message through our Contact Us page. Hewitt Tech is here to help.
Hewitt Tech’s SAIS bypass kits and products are sold for off-road, competition, or other emissions-exempt vehicles only. It is illegal to remove, dismantle, or otherwise cause to be inoperative any pollution control device required by federal, state, or local emissions law. No other applications are intended or implied. By installing or using this SAIS bypass kit, the vehicle owner and installer acknowledges and assumes ALL risks associated with its use.