P244B: Diesel Particulate Filter Differential Pressure Too High (Bank 1)

What does P244B mean?

P244B means the differential pressure across the diesel particulate filter is higher than the ECU expects, indicating the filter is heavily loaded with soot. The most common cause is a DPF that has failed to complete its passive regeneration cycle because the vehicle is driven mostly on short urban trips. Less commonly, the pressure sensor itself is reading high, the DPF substrate has melted or cracked internally, or there is a downstream exhaust restriction.

P244B is a emissions-related diagnostic trouble code classified as high severity. When your vehicle's ECU detects this condition, it stores P244B and illuminates the check engine light.

What are the symptoms of P244B?

If your vehicle has triggered P244B, you may notice one or more of these symptoms:

• Check engine light
• Noticeable loss of power and slow throttle response
• DPF warning light or message on dash
• Engine running rough at idle or under load
• Black smoke from exhaust under acceleration
• Fuel economy drops by 10 to 20 percent
• On severe blockage: limp mode (engine power reduced to 50 percent or less)

What causes P244B?

Here are the most common causes of P244B, ranked by how likely they are to be the culprit:

Is it safe to drive with P244B?

Generally yes, for short-term driving. Drivable in the short term, but treat as a priority repair. A heavily clogged DPF restricts exhaust flow, causes loss of power, can damage the turbocharger, and on some vehicles triggers limp mode after several drive cycles. Repair within days, not weeks.

How do you diagnose P244B?

Follow these steps to pinpoint the root cause of P244B:

1. Read live data: DPF soot mass (grams), distance since last regeneration, count of completed regenerations, and current differential pressure. A soot mass above 30 to 40 grams with no recent regeneration confirms the filter is overloaded
2. Before any parts replacement, attempt a forced regeneration with a scan tool that supports it (most independent garages have this capability). A successful forced regen drops the soot mass to under 5 grams and can resolve P244B without further repair, especially on a vehicle that has been driven on short trips
3. If forced regeneration fails or the soot mass refuses to drop, the DPF is either physically damaged or so loaded that off-vehicle cleaning is needed. Off-vehicle cleaning takes 1 to 2 days at a specialist and saves 60 to 80 percent versus DPF replacement
4. Compare the differential pressure reading to manufacturer specification at idle. A reading that is high at idle but normal under load points to a faulty sensor rather than a clogged filter. The sensor is far cheaper to replace than the DPF
5. Inspect the DPF substrate with a borescope through the inlet flange. A cracked or melted substrate is visible and cannot be cleaned, only replaced. Catastrophic regeneration events (often after a misfire or rich condition) destroy the substrate
6. Confirm there is no downstream restriction by checking the exhaust system from DPF outlet to tailpipe. A collapsed muffler or crushed pipe section will mimic a clogged DPF

How much does P244B cost to fix?

Repair costs for P244B vary depending on the root cause and your vehicle. Here are typical estimates:

P244B on specific vehicles

P244B behaves differently depending on your vehicle. Select your car below for model-specific causes, known issues, and adjusted cost estimates:

Related diagnostic codes

These codes are often seen alongside P244B or indicate related issues:

Common questions about P244B

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