The P20C9: Reductant Control Module Requested MIL Illumination indicates that the reductant control module has detected a fault and has requested the Malfunction Indicator Lamp (MIL) to be illuminated. This can occur due to various system issues that require attention, potentially related to a faulty control module or other components in the reductant system.
P20C9 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P20C9: Reductant Control Module Requested MIL Illumination |
| Is it serious? | Yes, this indicates the vehicle has an issue that requires immediate attention to maintain optimal operation and emissions control. |
| Possible causes | – Control module has requested MIL illumination due to a fault – Faulty reductant control module – System issues requiring attention |
| How to diagnose? | – Inspect the reductant control module for faults – Diagnose the reason for MIL illumination – Perform required repairs or replacements |
P20C9 Meaning
The P20C9 fault code signifies that the reductant control module has detected a fault within the system and has triggered the Malfunction Indicator Lamp (MIL) on the dashboard. This is a warning to the driver that there is a problem that needs to be addressed, possibly relating to the control module itself or another critical system in the vehicle. Immediate diagnosis is required to identify the exact cause.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for additional codes related to the reason for MIL illumination. | OBD-II Scanner |
| Inspect the Reductant Control Module | Use diagnostic tools to inspect the reductant control module for signs of failure or malfunction. | Diagnostic Tool |
| Diagnose the Reason for MIL Illumination | Investigate system-wide issues, including sensor failures, wiring problems, or any other issues reported by additional codes. | OBD-II Scanner, Multimeter |
| Check for Wiring Issues | Inspect wiring related to the reductant control module and associated components to ensure there are no disconnections or faults. | Flashlight, Multimeter |
| Repair or Replace Faulty Components | Based on diagnosis, perform necessary repairs or replace the faulty control module or associated components. | Replacement Parts, Tools |
| Clear the Code and Test Drive | After repairs, clear the code using an OBD-II scanner and test drive the vehicle to ensure the problem is resolved. | OBD-II Scanner, Vehicle Manual |
| Recheck for Codes | After the test drive, rescan the vehicle to ensure the P20C9 code and MIL illumination do not return. | OBD-II Scanner |
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