P044B - EGR Temperature Sensor B Circuit Range/Performance
Last updated:
System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P044B is stored when the Engine Control Unit (ECU) detects an implausible signal from EGR Temperature Sensor 'B'. This sensor is typically located at the outlet of the EGR cooler or in a secondary position. It uses an NTC thermistor logic where resistance decreases as temperature increases. The ECU compares the readings from this sensor against intake air temperature (IAT) and engine coolant temperature (ECT) sensors during cold starts and steady-state driving. If the voltage return is erratic or deviates from the modeled map, the ECU flags a performance fault. This affects the precision of Exhaust Gas Recirculation (EGR) flow control, impacting NOx emissions.
Possible Causes
Soot or carbon buildup on the sensor tip insulating the thermistor
Faulty EGR temperature sensor B (internal resistance failure)
High resistance or corrosion in the sensor connector
Restricted or failing EGR cooler affecting thermal transfer
Symptoms
Recommended Solution
Workflow
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
Do you also have
other fault codes?
See how P044B connects with your other fault codes. Our advanced analysis tool identifies causal relationships and root causes directly.