P044C: EGR Sensor C Circuit Low

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. P044C means its signal is below the lower limit. Ford petrol engines from 2020 set it below 0.25 V for 5 s – a value the sensor cannot produce, since 0.5 V already means −11 kPa – so the signal is shorted to ground, the 5 V supply is open or the sensor is faulty. EGR flow, hose and cooler checks are then suspended; MIL after two trips.

Symptoms

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

Most likely causes

• 5 V supply of the sensor open or shorted to ground
• Signal wire shorted to ground
• Sensor faulty internally
• Connector corroded or off

What to check, in order

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

1. Check the connector and any vacuum hoses
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Use live data to compare the commanded opening with the actual opening
4. Clean the valve and passages if they are clogged with carbon
5. Test the actuator with the scanner
6. 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 P044C means

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

Frequently asked questions

Can I keep driving with code P044C?

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 P044C?

The most common causes are: 5 V supply of the sensor open or shorted to ground; signal wire shorted to ground; sensor faulty internally.

Related codes

• P044DEGR Sensor C Circuit High
• P044BEGR Sensor C Circuit Range/Performance
• P044AEGR Sensor C Circuit
• P0405EGR Sensor A Circuit Low
• P0401EGR A Flow Insufficient Detected

Sources

• fordservicecontent.com: OBD Operations Summary Gasoline 2020 2023
• gsi.ext.gm.com: 18OBDG04 Engine Diagnostics
• 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.