P2458 Code: Diesel Particulate Filter Regeneration Duration

What the P2458 code means

The diesel particulate filter (DPF) traps soot from a diesel engine. When it fills up, the computer burns the soot off in a regeneration: it raises the exhaust temperature above 550 °C (1,020 °F) for a few minutes, usually while you drive at a steady speed. A differential pressure sensor measures the back pressure across the filter to estimate how much soot it holds.

If the regeneration does not reach temperature, or it gets cut off because the engine is shut off, the computer tries again. When it goes past the maximum time, it stores the P2458 code.

Before you replace the filter, rule out the things that stop it from regenerating: sensors, an EGR valve leaking soot, leaking injectors, a thermostat stuck open, or oil that is not rated for diesel particulate filters.

P2458 code symptoms

• Check engine light or DPF warning light on.
• Loss of power or limp mode.
• Cooling fan running after you shut off the engine during a regeneration.
• Higher fuel use.

Likely causes of the P2458 code

1. Short trips that interrupt the regeneration. The most frequent cause.
2. Not enough exhaust temperature because of a thermostat stuck open or the EGT sensors.
3. Faulty injector or oxidation catalyst, which do not make the heat.
4. Filter loaded with ash. Replace it if you do not know how old it is.

How to diagnose the P2458 code step by step

1. Read the estimated soot load and the differential pressure in the live data.
2. Check the pressure sensor hoses, which crack or clog.
3. Check the exhaust temperature and the EGT sensors.
4. Check the engine codes. Injectors, the EGR and the turbo can produce excess soot.
5. Try a forced regeneration with the scan tool, following the manufacturer conditions.

How to fix the P2458 code

• Do a regeneration on the road: 20 to 30 minutes at a steady highway speed.
• Run a forced regeneration with the scan tool if the soot load allows it.
• Repair the cause of the excess soot.
• Clean or replace the filter if it is loaded with ash.
• Use oil that meets the DPF specification (low ash).

Technical reference data

• Regeneration temperature: 550 to 650 °C (1,020 to 1,200 °F).
• Differential pressure with a clean filter at idle: normally a few millibars (well under 1 psi).
• Approximate values only: check the manufacturer data for your vehicle.

Brand-specific notes

Short city trips are the main reason regenerations get cut off. If the P2458 code keeps coming back, a longer highway drive is the cheapest first test.

P2458 on Diesel Vehicles From Many Makes

Common on diesels from Volkswagen, Audi, Seat, Peugeot, Citroen, Renault, Ford, Mercedes-Benz, BMW, Toyota Hilux, Nissan Navara and Chevrolet. Short city trips are the filter worst enemy.

Frequently asked questions about P2458