P244A: Diesel Particulate Filter Differential Pressure Too Low Bank 1

What it means

The differential pressure across the DPF is below the calibrated minimum even at higher loads. Often a sign of a damaged or missing filter substrate, or a leak in the sensing line.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

A differential-pressure sensor measures the pressure drop across the Bank 1 diesel particulate filter (DPF) to help the engine control module assess exhaust flow and filter loading. P244A sets when the measured pressure difference is below the calibrated minimum under conditions where the module expects more restriction. A damaged or missing filter substrate or a leak in the sensing line can cause that low reading.

Common causes

Most likely first.

1. Cracked or missing DPF substrate
2. Leak in pressure sensing line

Symptoms

• Check engine light or DPF warning light on
• Power loss / limp mode
• Increased fuel consumption
• Failed forced regeneration attempts

How to diagnose it

1. Review freeze-frame data and live DPF pressure readings at different engine loads, and check for related DPF or exhaust codes before drawing conclusions about the filter.
2. Inspect the Bank 1 differential-pressure sensor hoses and connections for cracks, disconnections, leaks, kinks, or heat damage.
3. With the engine off, check the sensor ports and hoses for blockage or damage that could distort the pressure reading.
4. Compare the differential-pressure sensor reading at rest and with the engine running against the manufacturer’s specification to assess sensor and circuit plausibility.
5. If the sensor and sensing lines check out, inspect the Bank 1 DPF for a damaged or missing substrate and check nearby exhaust joints for leaks.

Common fixes

• Reconnect or replace a leaking, cracked, or heat-damaged pressure-sensing hose.
• Clear an obstructed sensor port or replace damaged pressure tubing.
• Repair wiring or replace a faulty differential-pressure sensor if testing confirms the fault.
• Repair or replace a damaged Bank 1 DPF substrate as required.

Can I keep driving?

Because this code can accompany reduced power or limp mode, avoid towing, hard acceleration, and long trips until it is diagnosed. A damaged or missing DPF can increase emissions, while continued operation with a related fault may worsen power loss.