P246D
Particulate Filter Pressure Sensor A/B Correlation
Auxiliary emissions / diesel particulate filter
Generic OBD-II
Medium
What it means
P246D means the two particulate-filter pressure sensors (A and B) are reporting values that don't agree with each other. The ECM uses these to judge how much soot is in the filter, so a mismatch leaves it unable to trust the soot load and manage regeneration correctly. The usual culprit is one failing sensor or a blocked pressure hose rather than the filter itself.
Medium
Can I keep driving? Often drivable, but the ECM can't trust the filter's soot reading, so regeneration may be mismanaged — check it soon.
Common symptoms
What you'll notice
- Check-engine light on
- Regeneration happening too often or not at all
- Possible reduced power if the ECM defaults its DPF strategy
- Often no obvious driving symptom at first
Common causes
Most likely first
- Faulty DPF pressure sensor A or BLikely
- Blocked, kinked, or leaking pressure-sensor hosesCommon
- Wiring or connector fault on one of the sensor circuitsCommon
- A genuine pressure difference across the filter (partial blockage)Less often
- ECM fault (rare)Less often
How to diagnose & fix
Work through it in order
- Scan live data and compare the two pressure-sensor readings against each other.
- Inspect both sensors' hoses for blockage, cracks, or crossed/misrouted lines.
- Check the sensor connectors and wiring for corrosion or looseness.
- Compare readings to a known-good baseline to identify the drifting sensor.
- Replace the faulty pressure sensor once isolated.
FAQ
Quick answers
Is it safe to drive with P246D?+
Usually yes short-term, but because the filter's soot load is being misread, regeneration can go wrong. Have it diagnosed soon.
Can I just clear P246D?+
It returns as soon as the two sensors disagree again. Find the drifting sensor or blocked hose first.
Related codes
Often seen with P246D
Read & clear P246D yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX