Faulty EGR temperature sensor (internal open circuit or drift); Open circuit or high resistance in the sensor signal or ground wire; Corroded, loose or damaged connector at the sensor; Signal wire shorted to a voltage supply; Heat damage to wiring or the connector near the EGR cooler or exhaust; Fault in the engine control unit or its sensor supply.

P041D

EGR Temperature Sensor B 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
1D: FaultThe specific fault in that area

What it means

P041D means the engine control unit has detected a voltage in the EGR temperature sensor 'B' circuit that is higher than expected. This usually points to an open circuit, a short to a voltage supply, or a failed sensor. The ECU compares the signal with its expected range and sets the code when it stays out of range. Which sensor is 'B' and where it sits depends on the vehicle and engine.

Symptoms

Engine warning light on
Possible reduced performance or limp mode on some vehicles
Rough idle or hesitation, particularly if the EGR system is being disabled by the ECU
Increased exhaust smoke or a failed emissions test
Other EGR-related fault codes stored alongside

Possible causes

Faulty EGR temperature sensor (internal open circuit or drift)likely
Open circuit or high resistance in the sensor signal or ground wirelikely
Corroded, loose or damaged connector at the sensorlikely
Signal wire shorted to a voltage supplypossible
Heat damage to wiring or the connector near the EGR cooler or exhaustpossible
Fault in the engine control unit or its sensor supplyrare

How to diagnose

Read all stored codes and freeze frame data to see engine conditions when the fault set, and note any other EGR or sensor codes.
Check for a manufacturer technical bulletin or known issues for this model and engine, as sensor location and 'B' designation vary.
Visually inspect the sensor, wiring and connector for heat damage, chafing, corrosion, or water ingress.
With the engine cold, compare the live EGR temperature reading with coolant or intake air temperature; a reading stuck at the maximum suggests an open circuit.
Unplug the sensor and check the live value; if it stays high, inspect the wiring and ECU side, and if it changes, suspect the sensor.
Measure the sensor resistance against the manufacturer's specification, ideally at a known temperature.
Test the signal wire for continuity, for a short to voltage, and the ground connection back to the ECU.
Check the reference voltage and ground at the ECU connector before suspecting the control unit.

How to fix

Replace the EGR temperature sensor if it fails resistance or live data checks.
Repair or replace damaged wiring, correcting any open circuit or short to supply.
Clean or replace corroded or damaged connector terminals and fit new connector housings where needed.
Re-route and secure wiring away from hot components, repairing any heat damage.
If the control unit is proven faulty, repair or replace it and have it programmed correctly for the vehicle.
Clear the codes after repair and road test to confirm the fault does not return.

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but book it in soon. A faulty EGR system can affect emissions and performance, and if the car enters limp mode, limit driving until it is repaired.

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