P2456

Particulate Filter Pressure Sensor A Circuit Intermittent/Erratic

Q: Is it safe to drive with P2456?

Short term usually yes, but because the ECM can't trust the filter pressure reading it may block regeneration or drop into reduced power, so get it checked soon.

Q: Can I just clear P2456?

It clears, but an intermittent wiring or connector fault will set it again. Find and fix the loose connection or failing sensor first.

Auxiliary emissions control (diesel) Generic OBD-II Medium

What it means

P2456 means the diesel particulate filter's "A" pressure sensor is sending an unstable or dropping-out signal to the engine computer. The ECM uses this reading to judge how clogged the filter is and when to run a regeneration, so an erratic signal is usually a wiring, connector, or sensor fault rather than an engine problem.

Medium

Can I keep driving? Usually drivable, but the ECM can't reliably monitor the particulate filter, so it may trigger a regen fault or reduced-power mode over time.

Real-world scan data

Seen in

209

scans in the past year

Found in

<0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of P2456 scans

P0645in 35.9% of scans

P2455in 29.7% of scans

P242Fin 26.8% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Signal that drops out or reads erratically to the ECM
Possible failed or incomplete DPF regeneration
Occasional reduced-power / limp mode if the fault repeats

Common causes

Most likely first

Loose, corroded, or backed-out connector at the particulate filter pressure sensorLikely
Chafed, pinched, or intermittently shorting wiring in the sensor circuitCommon
Failing particulate filter differential-pressure sensorCommon
Blocked, cracked, or moisture-filled pressure hoses to the sensorLess often
Poor ground or intermittent ECM connectionLess often

How to diagnose & fix

Work through it in order

Read freeze-frame data, then wiggle-test the sensor connector and harness to reproduce the dropout.
Inspect the connector and pins for corrosion, spread terminals, or moisture; clean and reseat.
Check the pressure hoses to the sensor for cracks, soot blockage, or trapped condensation.
Measure the sensor's reference voltage, ground, and signal against spec; back-probe while wiggling the harness.
If wiring and connections are good, replace the differential-pressure sensor, then clear and road-test.

FAQ

Quick answers

Is it safe to drive with P2456?+

Short term usually yes, but because the ECM can't trust the filter pressure reading it may block regeneration or drop into reduced power, so get it checked soon.

Can I just clear P2456?+

It clears, but an intermittent wiring or connector fault will set it again. Find and fix the loose connection or failing sensor first.

Read & clear P2456 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX