When it comes to automotive trouble codes, Ford P1812 is one of the most common codes that you may come across. This code has to do with a 4×4 Mode Select Circuit Failure, meaning that the Mode Select Switch (MSS) is not communicating the operator’s choice to the 4X4 control module. This can lead to issues with the transfer case clutch and transfer case shift motor. In order to diagnose and repair this problem, it is important to check the necessary inputs and outputs of the 4X4 control module, components of the transfer case, and halfshafts. In addition, it is necessary to check all circuits for opens and shorts to power or ground. Thankfully, there is a service bulletin available to help with this issue. The bulletin, SSM50322, can provide valuable information for diagnosing and repairing the Ford P1812 code.
Causes and Solutions for Ford P1812 Code
| Cause | Solution |
|---|---|
| Open circuit or short to battery sensed by 4×4 control module | Check necessary inputs and outputs of the 4X4 control module |
| Correct mode not selected for self-test | Check components of the transfer case and halfshafts |
| Circuits have opens and shorts to power or ground | Check all circuits for opens and shorts to power or ground |
| Mode Select Switch (MSS) not communicating the operator’s choice to the 4X4 control module | Check Mode Select Switch (MSS) and the 4X4 control module |
Open Circuit or Short to Battery Sensed by 4×4 Control Module
When a Ford P1812 code is detected, it is likely due to an open circuit or short to battery sensed by the 4×4 control module. To diagnose and repair this issue, you’ll need to check the necessary inputs and outputs of the 4X4 control module. This may involve checking the transfer case clutch and transfer case shift motor, as well as the components of the transfer case and the halfshafts. It is also important to check all of the circuits to see if they have opens or shorts to power or ground.
Correct Mode Not Selected for Self-Test
In some cases, the Ford P1812 code may be related to the correct mode not being selected for the self-test. This can be due to a malfunction in the Mode Select Switch (MSS) or the 4X4 control module. When diagnosing this issue, it is important to check these components to ensure that the operator’s choice is being communicated correctly to the control module.
Service Bulletin SSM50322
Thankfully, Ford has created a service bulletin, SSM50322, to help with diagnosing and repairing the Ford P1812 code. This bulletin includes valuable information about how to troubleshoot the issue and how to make the necessary repairs. It is important to follow the instructions in the bulletin carefully to ensure that the issue is properly diagnosed and repaired.
Conclusion
The Ford P1812 code is a common issue that can be difficult to diagnose and repair. It is important to check the necessary inputs and outputs of the 4X4 control module, as well as the components of the transfer case and halfshafts. Additionally, it is important to check all circuits for opens and shorts to power or ground. Thankfully, Ford has created a service bulletin, SSM50322, to provide information on how to diagnose and repair the Ford P1812 Code. Following these instructions carefully can help ensure that the issue is properly taken care of.
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