Faulty EGR sensor C (flow, pressure, temperature or position sensor, depending on the vehicle); Damaged, chafed or corroded wiring, or a poor connector, at the sensor; Open circuit in the sensor ground or short to voltage on the signal wire; Sooted or blocked EGR passages or valve affecting sensor readings; Faulty or sticking EGR valve with integrated sensor; Faulty sensor reference supply or a fault in the engine control unit.

P044D

EGR Sensor C Circuit High.

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
4D: FaultThe specific fault in that area

What it means

P044D is a generic powertrain code meaning the engine control unit has detected a high voltage or signal in the circuit of exhaust gas recirculation (EGR) sensor 'C'. The signal has gone above the expected range, which usually points to a short to voltage, an open circuit in the signal or ground wire, or a faulty sensor. Which sensor is 'C' (for example a flow, pressure, temperature or valve position sensor) depends on the vehicle and engine, so check the manufacturer's information.

Symptoms

Engine warning light on
Rough idle or hesitation under load
Poor fuel economy
Increased exhaust smoke or a smell of fuel
Reduced power or the car entering limp mode on some models
Failed emissions test

Possible causes

Faulty EGR sensor C (flow, pressure, temperature or position sensor, depending on the vehicle)likely
Damaged, chafed or corroded wiring, or a poor connector, at the sensorlikely
Open circuit in the sensor ground or short to voltage on the signal wirelikely
Sooted or blocked EGR passages or valve affecting sensor readingspossible
Faulty or sticking EGR valve with integrated sensorpossible
Faulty sensor reference supply or a fault in the engine control unitrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, such as engine temperature, load and speed, when the fault set.
Check the manufacturer's information to identify which sensor is 'C' on this model and engine, and find its wiring diagram.
Visually inspect the sensor, its wiring and connector for heat damage, chafing, corrosion, bent pins or water ingress.
With the ignition on, view the sensor's live data and compare it to the expected values, noting whether it is stuck high.
Unplug the sensor and test the reference supply, signal and ground with a multimeter against the wiring diagram.
Check the signal wire for a short to voltage, and the ground wire for an open circuit or high resistance.
Inspect the EGR valve, pipes and passages for heavy carbon build-up or blockage, and check the valve operates correctly.
Clear the code and road test, then recheck live data to confirm the fix.

How to fix

Repair or replace damaged wiring and renew corroded or loose connector terminals.
Replace the EGR sensor C if it is faulty and is available as a separate part.
Replace the EGR valve assembly if the sensor is built into it and is faulty.
Clean or clear carbon-blocked EGR passages and components according to the manufacturer's procedure.
Restore a missing or poor ground or supply connection found during testing.

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but book a repair soon as the EGR system may not work properly and can affect running, fuel economy and emissions. If the car goes into limp mode or runs badly, limit driving and have it checked promptly.

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