P044B: EGR Sensor C Circuit Range/Performance

Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. What EGR sensor C is depends on the maker: on Ford petrol engines from 2020 it is the DPFE sensor, which measures the pressure drop across an orifice in the EGR pipe (sensor A there is the valve position sensor); GM diesels assign it to the position sensor of a low-pressure EGR valve, but only within fault groups. P044B means its signal is electrically valid but implausible – for example a pressure difference with the valve closed, or no reaction when it opens. No manufacturer document available to us uses this code; Ford checks the DPFE plausibility under its own codes P139A–P139C (hoses swapped, front or rear hose off or blocked). EGR flow diagnosis is then suspended.

Medium severity. Can I keep driving?You can normally drive in moderation, but get it repaired soon: if the valve is stuck open, the engine may idle very poorly.

Symptoms

Check engine light on
Usually no change in driving
EGR readiness not set, EGR possibly switched off

Most likely causes

Pressure hoses off, swapped or blocked (soot, condensate)
Sensor zero point drifted
Orifice or EGR pipe coked
Contact resistance in the connector

What to check, in order

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

Check the connector and any vacuum hoses
Compare the reading with other engine data while varying the engine speed.
Use live data to compare the commanded opening with the actual opening
Clean the valve and passages if they are clogged with carbon
Test the actuator with the scanner
Replace the valve if it still does not follow the command after cleaning

Good to know

Repair difficulty: easy
It affects emissions.

What each character of P044B means

P: Powertrain: engine and transmission
0: Generic code: same on every make
4: Emissions
4B: Specific fault in that system

Frequently asked questions

Can I keep driving with code P044B?

You can normally drive in moderation, but get it repaired soon: if the valve is stuck open, the engine may idle very poorly.

What causes code P044B?

The most common causes are: pressure hoses off, swapped or blocked (soot, condensate); sensor zero point drifted; orifice or EGR pipe coked.

Related codes

Sources

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.