P044A
EGR Sensor C Circuit.
- 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
- 4A
- FaultThe specific fault in that area
What it means
P044A means the engine control unit has detected a fault in the circuit of EGR (exhaust gas recirculation) sensor 'C'. The generic definition does not say which sensor this is, as the labelling of sensors A, B and C and their type (position, temperature or pressure) depends on the vehicle. The code is set when the sensor signal or its supply or ground is outside the expected electrical range, or does not make sense for the operating conditions.
Symptoms
- Engine management light on
- Rough or unstable idle
- Hesitation or poor response under load
- Reduced power or the car going into a limited performance mode
- Increased fuel consumption
- Failed emissions test or higher exhaust emissions
Possible causes
- Faulty EGR sensor 'C' (for example contaminated, heat-damaged or failed internally)likely
- Damaged, chafed, corroded or loose wiring or connector to the sensor, including open or short circuitslikely
- Sensor sensing port or pipe blocked with carbon or soot, giving an implausible signal (applies to pressure-type sensors)possible
- Faulty sensor supply voltage or ground, for example a fault in a shared reference circuitpossible
- Heat damage to wiring or connector near the EGR valve or exhaust pipeworkpossible
- Fault inside the engine control unit or an outdated calibration, where the manufacturer has issued an update for this faultrare
How to diagnose
- Read all stored and pending codes and the freeze frame data. Note engine load, temperature and speed when the fault set, and check for other EGR, MAP or sensor supply codes.
- Check the manufacturer information to find out which sensor is 'C' on this model and engine, and what type it is.
- Inspect the sensor, its wiring and connector for heat damage, chafing, corrosion, water ingress and bent or pushed-back pins.
- Check any hoses or pipes feeding the sensor for splits, blockages or carbon build-up, if it is a pressure-type sensor.
- With the scan tool live data, watch the sensor reading with the ignition on and at idle and compare it with the expected values for this model.
- Measure the sensor supply voltage and ground at the connector, and check the signal wire for continuity and for shorts to ground or voltage.
- Check the EGR valve operation and look for heavy carbon fouling that may be affecting the readings.
- Check for any technical bulletins or calibration updates relating to this code for the vehicle.
How to fix
- Repair or replace damaged wiring, terminals or the connector, and secure the harness away from heat.
- Replace the EGR sensor 'C' if the readings or electrical tests show it has failed.
- Clean or replace blocked sensor pipes or ports, and clean or replace the EGR components if they are heavily fouled.
- Restore a correct supply or ground by repairing the shared circuit fault.
- Fit a manufacturer-approved calibration update only if an outdated or faulty calibration is confirmed as a cause.
- Clear the codes after the repair and road test to confirm the fault does not return.
Can I keep driving?
The car can usually be driven short distances, but get it checked soon because the engine may run poorly, use more fuel and produce higher emissions. If power is noticeably reduced or the engine runs roughly, limit driving until it is repaired.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.