P2458 Diesel Particulate Filter Regeneration Duration
OBD-II Trouble Code Technical Description
Diesel Particulate Filter Regeneration Duration
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to all 1996-newer vehicles (Ford, Dodge, GMC, Chevrolet, Mercedes, VW, etc.). Although generic, the specific repair steps may vary depending on make/model.
When I encounter a stored code P2458, I know that the powertrain control module (PCM) has detected a malfunction in the diesel particulate filter (DPF) regeneration system. This particular code indicates that the regeneration process has not been completed properly. Obviously, use of this code is limited to diesel powered vehicles.
Designed to remove ninety-percent of carbon particles (soot) from diesel engine exhaust, DPF systems are critical in helping automakers meet today’s strict federal guidelines for clean burning diesel engines. Maybe you have noticed that modern diesel powered vehicles smoke far less than the diesel powered vehicles of yesteryear. Complex DPF systems are responsible for that.
Although there are several varying designs of DPF systems, most of them function in a similar manner. The DPF housing is a large steel muffler shaped device that contains a filtration element. Large soot particles are trapped by the filtration element and exhaust gases are allowed to flow through and exit the tailpipe. In some configurations, the DPF contains wall fibers that attract larger soot particles as they enter the housing. Other systems contain a loose web assembly that fills virtually the entire housing. The holes in the filtration device are sized so that larger soot particles are trapped and exhaust gases flow through.
In any case, when the filtration element has accumulated a certain degree of soot particles, it becomes partially clogged and exhaust back pressure increases. DPF back pressure is monitored by the PCM using a pressure sensor. Once back pressure reaches a particular level, the PCM takes measures to regenerate the filtration element.
In order for the filtration element to be regenerated, the temperature inside the DPF must reach approximately 1,200-degrees Fahrenheit. A specialized injection system is used to accomplish this in most instances. The electronically controlled injection procedure introduces a flammable chemical component, such as diesel fuel or diesel exhaust fluid, into the DPF. Once the specialized fluid has been introduced, the trapped soot particles are incinerated and released into the atmosphere (via the tailpipe) as harmless ions of nitrogen and water.
Active DPF regeneration systems are activated automatically by the PCM and the process takes place while the vehicle is being driven. Passive DPF regeneration systems require input from the operator (after the PCM has exhibited a cautionary warning) and usually takes place after the vehicle is parked. The regeneration procedure for passive systems may take hours to complete. I recommend that you check your vehicle owner’s manual to see with which type of DPF system your vehicle is equipped.
If the PCM detects that the regeneration process has not been completed as specified, or if exhaust pressure fails to reach the desired level, a P2458 could be stored and a malfunction indicator lamp may be illuminated.
Symptoms & Severity
Because DPF regeneration is crucial to maintaining desired exhaust back pressure, this code should be addressed with some degree of urgency. Symptoms of a P2458 code may include:
Other DPF codes will likely accompany the P2458 Excessive black smoke from the exhaust Inability to produce and maintain desired RPM levels Increased engine temperature Overheated DPR housing or other exhaust componentsCauses
Potential causes for this code to set are:
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