Faulty EGR sensor C (position, pressure or temperature, depending on the model) reading out of range; Damaged, chafed or shorted-to-ground sensor signal wire; Corroded, loose or contaminated connector terminals at the sensor or control unit; Open circuit or high resistance in the sensor reference voltage supply or ground; Sooty or sticking EGR valve or blocked EGR passages affecting the sensor reading; Fault inside the engine control unit.

P044C

EGR Sensor C Circuit Low.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
4: AreaAuxiliary emission controls
4C: FaultThe specific fault in that area

What it means

P044C is a generic powertrain code meaning the engine control unit has detected a low voltage signal from the circuit of exhaust gas recirculation (EGR) sensor C. The signal has fallen below the expected range, which usually points to a short to ground, an open circuit, or a faulty sensor. Which sensor is called 'C' (for example a position, pressure or temperature sensor) depends on the vehicle and engine, so check the manufacturer's information for your model.

Symptoms

Engine warning light on
Rough or unstable idle
Hesitation or reduced power under acceleration
Poor fuel economy
Possible pinging or knocking under load
Car may enter a reduced power mode on some models

Possible causes

Faulty EGR sensor C (position, pressure or temperature, depending on the model) reading out of rangelikely
Damaged, chafed or shorted-to-ground sensor signal wirelikely
Corroded, loose or contaminated connector terminals at the sensor or control unitlikely
Open circuit or high resistance in the sensor reference voltage supply or groundpossible
Sooty or sticking EGR valve or blocked EGR passages affecting the sensor readingpossible
Fault inside the engine control unitrare

How to diagnose

Read the freeze frame data and any other stored codes, noting engine temperature, load and speed when the fault set, and address related EGR or sensor supply codes first.
Check the manufacturer's information to identify what EGR sensor C is on this engine and where it is located.
Visually inspect the sensor, its wiring and connectors for heat damage, chafing, oil contamination, water ingress and corrosion.
With the ignition on, check the sensor reference voltage and ground at the connector against the manufacturer's specification.
Monitor the sensor's live data reading and compare it with expected values at idle and when the EGR is commanded open and closed.
Check the signal wire for a short to ground and for continuity and resistance back to the control unit, with the connector unplugged and the ignition off.
Inspect the EGR valve and passages for heavy carbon build-up or a sticking valve, as this can affect the sensor reading.
If wiring and supply are good, test or substitute the sensor as per the manufacturer's procedure before suspecting the control unit.

How to fix

Replace the EGR sensor C if its readings or electrical values are out of specification.
Repair or replace damaged wiring, correcting any short to ground or open circuit.
Clean or replace corroded connector terminals and ensure the connector is fully seated and sealed.
Clean or replace the EGR valve and clear blocked passages if contamination is affecting the sensor or valve operation.
Check for an updated control unit software calibration only if the manufacturer lists one for this fault, and have the control unit repaired or replaced as a last resort.

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but book it in soon as poor running and increased emissions may get worse. If it goes into reduced power or runs very roughly, limit driving until it is checked.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.