P246D: Particulate Filter Pressure Sensor A/B Correlation

P246D compares two pressure readings at the particulate filter that ought to agree under steady conditions. Which sensor is A and which is B is decided by each manufacturer. Ford's 2013 to 2015 diesel summaries use it as a rationality test between the filter pressure sensor DPFP and the delta pressure sensor DPS: with coolant above 70 °C, ambient pressure above 745 hPa, filter inlet temperature between 125 and 425 °C and exhaust flow of 200 to 600 kg/h, the code sets once the two differ by over 1.5 kPa, evaluated over about 2 s. Typical findings are swapped, kinked or leaking sensing hoses, water in a line or one sensor drifting while its circuit still passes. Pure electrical faults have their own codes (P2452 ff. and P245E ff.). With a doubtful pressure value the soot estimate and regeneration timing suffer.

Symptoms

• MIL on
• Regeneration too early, too late or suspended
• Pressure values of the two sensors disagree in live data

Most likely causes

• Sensing hoses swapped, kinked or leaking
• Water or soot in a sensing line
• One pressure sensor drifting out of calibration

What to check, in order

Start with the simplest. You can tick off each step.

1. Read the soot load and differential pressure with a scanner
2. Compare both signals at the same time in live data and check any recent installation work.
3. Check the differential pressure sensor's hoses
4. Check the temperatures before and after the filter
5. Fix any fuel injection or EGR codes before regenerating
6. Perform a regeneration while driving or at a repair shop when the diagnosis allows it

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P246D means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 4: Emissions
• 6D: Specific fault in that system

Frequently asked questions

Can I keep driving with code P246D?

If the light is on steadily, take a highway drive or go to a repair shop soon. If the car is in limp mode or the light is flashing, do not push the engine.

What causes code P246D?

The most common causes are: sensing hoses swapped, kinked or leaking; water or soot in a sensing line; one pressure sensor drifting out of calibration.

Related codes

• P2452Diesel Particulate Filter Pressure Sensor A Circuit
• P2453Diesel Particulate Filter Pressure Sensor A Circuit Range/Performance
• P245EParticulate Filter Pressure Sensor B Circuit
• P245FParticulate Filter Pressure Sensor B Circuit Range/Performance
• P244ADiesel Particulate Filter Differential Pressure Too Low (Bank 1)
• P244BDiesel Particulate Filter Differential Pressure Too High (Bank 1)

Sources

• fordservicecontent.com: DOBDSM1501
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.