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.

Likely causes

Symptoms

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

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: fordservicecontent.com, law.cornell.edu.