The Toyota Code P0412 is a secondary air injection system switching valve “A” circuit issue. It affects the air pump, air switching valve, air injection control driver, and the ECM. After a cold engine start, all of the following conditions must be met: the secondary air injection system must be off, the diagnostic signal from the air injection control driver must be 40%, and the battery voltage must be 8V or higher. This code can be caused by an open in the air switching valve drive circuit, a short between the ASV drive circuit and body ground, an air injection control driver, an air switching valve, or an ECM.
Causes and Solutions of Toyota Code P0412
| Cause | Solution |
|---|---|
| Open in ASV drive circuit | Check the electrical connections and repair any damage. |
| Short between ASV drive circuit and body ground | Check the connections and replace any broken parts. |
| Air Injection Control Driver (AID) | Replace the AID. |
| Air Switching Valve (ASV) | Replace the ASV. |
| ECM | Replace the ECM. |
The Toyota Code P0412 is a secondary air injection system switching valve “A” circuit issue that can be identified by a check engine light. It can be caused by a variety of issues, including an open in the air switching valve drive circuit, a short between the ASV drive circuit and body ground, an air injection control driver, an air switching valve, or an ECM. To diagnose and repair this issue, it is important to check the electrical connections, replace any broken parts, and ultimately replace the AID, ASV, or ECM if necessary. This article provides a comprehensive list of the causes and solutions of the Toyota Code P0412.
Open in ASV Drive Circuit
The Toyota Code P0412 can be caused by an open in the air switching valve (ASV) drive circuit. This issue can be identified by a diagnostic signal from the air injection control driver that reads 40% or lower. To repair this issue, it is important to check the electrical connections and repair any damage.
Short Between ASV Drive Circuit and Body Ground
A short between the ASV drive circuit and body ground can also cause the Toyota Code P0412. This issue can be identified by a diagnostic signal from the air injection control driver that reads 40% or lower. To repair this issue, it is important to check the electrical connections and replace any broken parts.
Air Injection Control Driver (AID)
The Toyota Code P0412 can also be caused by an air injection control driver (AID). This issue can be identified by a check engine light and trouble code. To repair this issue, it is important to replace the AID.
Air Switching Valve (ASV)
The Toyota Code P0412 can also be caused by an air switching valve (ASV). This issue can be identified by a check engine light and trouble code. To repair this issue, it is important to replace the ASV.
ECM
The Toyota Code P0412 can also be caused by an ECM. This issue can be identified by a check engine light and trouble code. To repair this issue, it is important to replace the ECM.
Conclusion: A Comprehensive Guide to Toyota Code P0412
The Toyota Code P0412 is a secondary air injection system switching valve “A” circuit issue that can be caused by a variety of issues. To diagnose and repair this issue, it is important to check the electrical connections, replace any broken parts, and ultimately replace the AID, ASV, or ECM if necessary. It is important to remember the Toyota Code P0412 when diagnosing and repairing any issues related to the secondary air injection system.
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