The P246C: Diesel Particulate Filter Restriction – Forced Limited Power code indicates that the diesel particulate filter (DPF) is restricted due to clogging, which has triggered a forced limited power mode to protect the engine. This issue usually arises when the DPF is excessively clogged and cannot regenerate properly, leading to a restricted exhaust flow that impairs engine performance.
P246C – Quick Overview
| Code | Information |
|---|---|
| Meaning | P246C: Diesel Particulate Filter Restriction – Forced Limited Power |
| Is it serious? | High – restricted DPF can lead to severe engine performance issues, increased emissions, and potential engine damage if not addressed promptly. |
| Possible causes | – DPF restriction leading to forced limited power – Clogged diesel particulate filter – Issues with the regeneration process |
| How to diagnose? | – Inspect the diesel particulate filter for clogging – Check the regeneration process – Replace the filter or address regeneration issues as needed |
P246C Meaning
The P246C: Diesel Particulate Filter Restriction – Forced Limited Power code means that the DPF is significantly restricted due to accumulated soot, triggering a power-limited mode to protect the engine. This occurs when the DPF fails to regenerate properly, leading to an inability to maintain optimal exhaust flow. The forced limited power mode reduces power output to minimize further damage. It may result from an ineffective regeneration process or an already overloaded DPF that cannot be cleaned by normal driving.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to determine if there are any other related fault codes. Related codes may help identify underlying issues affecting the DPF or regeneration process. | OBD-II Scanner |
| Inspect the Diesel Particulate Filter (DPF) | Visually inspect the DPF to check for signs of excessive soot buildup or blockage. This may require removing the DPF to determine the extent of clogging. | Flashlight, Safety Gloves |
| Check DPF Differential Pressure | Use a diagnostic tool to monitor the DPF differential pressure sensor. High readings typically indicate excessive soot accumulation in the DPF, confirming the restriction. | Diagnostic Tool |
| Verify Regeneration History | Use an OBD-II scanner to check the vehicle’s DPF regeneration history. Determine if the DPF has been unable to regenerate effectively due to incorrect conditions or system faults. | OBD-II Scanner |
| Inspect the Regeneration Process | Check the sensors involved in the regeneration process, including exhaust temperature sensors and pressure sensors, to ensure they are functioning correctly and allowing regeneration to occur. | Multimeter, Diagnostic Tool |
| Perform a Forced DPF Regeneration | If the DPF is clogged but not damaged, perform a forced regeneration using a diagnostic tool to burn off the excess soot. Monitor temperature and pressure readings to ensure proper completion. | Diagnostic Tool |
| Replace DPF if Needed | If the DPF is too clogged for successful regeneration or is damaged, replace the DPF to restore exhaust flow and vehicle performance. | Replacement DPF, Wrench Set |
| Repair Faulty Components | If sensors or components that affect regeneration are found to be faulty, repair or replace them to ensure that future regeneration cycles can occur as required. | Replacement Sensors, Wiring Repair Kit |
| Clear the Code and Test Drive | After repairs or replacement, clear the P246C code using an OBD-II scanner. Take the vehicle for a test drive to verify that the DPF is functioning correctly and that no further power restrictions are imposed. | OBD-II Scanner, Vehicle Owner’s Manual |
| Recheck for Codes | Re-scan the vehicle to confirm that the P246C code has not returned. If the code persists, further diagnostics may be needed to determine any unresolved issues affecting the DPF system. | OBD-II Scanner |
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Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)