P243A: Particulate Filter Restriction Ash Accumulation Bank 2

What it means

The diesel particulate filter on bank 2 reports backpressure attributable to ash (non-combustible residue from oil and fuel additives, not removable by regeneration). The filter has reached the end of its service life and needs cleaning or replacement.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The diesel particulate filter (DPF) on bank 2 traps soot from the exhaust, while ash from oil and fuel additives remains in the filter after regeneration. This code indicates that ash has accumulated enough to restrict the bank 2 filter; regeneration burns soot but cannot remove this ash.

Common causes

Most likely first.

1. DPF ash accumulation restricting exhaust flow
2. Excessive oil consumption adding ash to the filter
3. High-ash engine oil or fuel additives

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. Use a scan tool to record freeze-frame data and check bank 2 DPF restriction, differential pressure, ash estimate, and regeneration history.
2. Inspect the bank 2 DPF pressure-sensor hoses and connections for leaks, blockage, heat damage, or incorrect routing that could distort the reading.
3. Check for oil consumption, oil leaks into the exhaust, and use of oil or additives that may increase ash accumulation.
4. Compare bank 2 pressure readings at idle and under load with the manufacturer's specification, and check the sensor and exhaust temperature readings for plausibility.
5. If sensor readings support a real restriction, have the bank 2 filter assessed for ash cleaning or replacement; do not rely on regeneration to remove ash.

Common fixes

• Repair leaking or damaged bank 2 DPF pressure-sensor hoses.
• Repair a confirmed faulty DPF pressure sensor or its wiring.
• Correct excessive oil consumption or use of unsuitable high-ash oil or additives.
• Have the bank 2 DPF professionally cleaned for ash or replace it if cleaning is not suitable.

Can I keep driving?

Power loss or a DPF warning means you should avoid towing, steep climbs, and hard acceleration, and arrange service promptly. Continued driving with a restricted bank 2 DPF can worsen fuel use and exhaust restriction; a regeneration will not remove accumulated ash.