Fault code P0044 – a step-by-step guide to diagnosing and fixing it

Error code P0044 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system detects a fault in the heating circuit of lambda sensor 3, bank 1, which has a low resistance. This DTC P0044 relates to the heating function of the oxygen sensor after the catalytic converter and can occur with different manufacturers, whereby the exact position of the affected sensor can vary.

What causes can this fault code have?

• Defective lambda sensor heater
• Damaged cable connections to the lambda sensor
• Corroded or loose plug connections
• Short circuit in the heater circuit
• Defective engine control unit (ECM/PCM)
• Blown fuse in the lambda sensor heating circuit
• Faulty earth connection of the lambda sensor

What symptoms occur in parallel with fault code P0044?

• Increased fuel consumption: The vehicle consumes more fuel than usual
• Poor exhaust values: Increased emission values during the emissions test
• Uneven engine running: The engine runs unevenly, especially when idling
• Delayed catalytic converter warm-up: Longer warm-up phase of the exhaust system
• Check engine light: Permanent illumination of the check engine light

How can the problem with error code P0044 be rectified?

• The repair requires a systematic diagnosis of the lambda sensor heating circuit and its components.
• Replacement of the defective lambda sensor including heating element if the resistance is out of specification
• Repair or replacement of damaged cables and plug connections in the sensor heating circuit
• Cleaning corroded contacts and ensuring a stable electrical connection
• Checking and replacing blown fuses in the lambda sensor circuit
• Repairing the earth connection by cleaning the earth points and replacing corroded cables
• Reprogramming or replacement of the engine control unit in the event of internal errors in the heating circuit control unit