When a Chevrolet vehicle is displaying the P21AB code, it is a sign of an issue with the reductant level sensor 2 circuit high voltage. This code can cause a number of problems both in the short and long term, and can be tricky to diagnose and fix. Understanding the causes and solutions to this code can help owners of Chevy vehicles to better understand the issue and determine the best way to move forward. In this article, we will explore the Chevrolet P21AB Code and discuss the causes and solutions associated with it.
Causes and Solutions of Chevrolet P21AB Code
| Cause | Solution |
|---|---|
| P203D, P21AB, and P21B0 | Refer to the service bulletins for more detailed instructions. |
| The ECM receives a serial data message from the reductant sensor module that the emission reduction fluid tank level sensor 1, 2 or 3 voltage is between 3.56-4.74 V for greater than 3 s. A voltage within this range indicates an open circuit. | Check the wiring, connectors, and related electrical components. |
| The ECM receives a serial data message from the reductant sensor module that the emission reduction fluid tank level sensor 1, 2 or 3 voltage is greater than 4.74 V for greater than 3 s. A voltage within this range indicates a short to voltage. | Check the emission reduction fluid tank level sensor 1, 2 or 3 voltage. |
| Engine speed is greater than 600 RPM | Replace the ECM or related parts. |
P203D, P21AB, and P21B0
When a Chevrolet vehicle is displaying any of the codes P203D, P21AB, or P21B0, it is a sign that there may be an issue with the reductant level sensor 2 circuit high voltage. All of these codes can cause a variety of problems, both in the short and long term, and can be difficult to diagnose and fix. Owners of Chevy vehicles will need to refer to the service bulletins for more detailed instructions on how to troubleshoot the issue.
The ECM Receives a Serial Data Message
When the ECM receives a serial data message from the reductant sensor module, indicating that the emission reduction fluid tank level sensor 1, 2, or 3 voltage is between 3.56 to 4.74 volts for longer than three seconds, it may be indicative of an open circuit. In this case, owners of Chevy vehicles should check the wiring, connectors, and related electrical components.
The ECM Receives a High Voltage Message
On the other hand, if the ECM receives a serial data message from the reductant sensor module that the emission reduction fluid tank level sensor 1, 2, or 3 voltage is greater than 4.74 volts for longer than three seconds, it may be indicative of a short to voltage. In this case, owners of Chevy vehicles should check the emission reduction fluid tank level sensor 1, 2, or 3 voltage.
Engine Speed is Greater than 600 RPM
If an engine speed greater than 600 RPM is detected, the ECM may require replacement or related parts may need to be replaced. This is a sign that the Chevrolet P21AB Code is more serious and may require more significant intervention.
Conclusion
The Chevrolet P21AB Code is a sign of an issue with the reductant level sensor 2 circuit high voltage. This code can cause a variety of problems in the short and long term and can be difficult to diagnose and fix. Understanding the causes and solutions associated with the code can help owners of Chevy vehicles to better understand the issue and determine the best way to move forward. Depending on the cause of the code, owners may need to check wiring and connectors, the emission reduction fluid tank level sensor voltage, or replace the ECM or related parts.
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