Fault code P0119 – a step-by-step guide to diagnosing and fixing it

Error code P0119 is displayed and the check engine light is on - what does this mean?

DTC P0119 is triggered by the OBD system when the engine control unit detects an intermittent or implausible signal from the coolant temperature sensor (ECT). This trouble code indicates problems with the coolant temperature circuit, which is crucial for optimum engine control. For various manufacturers, this fault code can also be referred to as "Engine Coolant Temperature Circuit Intermittent".

What can cause this error code?

• Defective coolant temperature sensor (ECT sensor)
• Damaged or corroded cable connections to the temperature sensor
• Loose or defective plug connections on the ECT sensor
• Short circuit or interruption in the sensor wiring
• Defective engine control unit (rare)
• Insufficient coolant level or air bubbles in the cooling system
• Defective thermostat leading to incorrect temperature values

What symptoms occur in parallel with fault code P0119?

• Starting problems: The vehicle is difficult to start, especially when the engine is cold
• Uneven idling: The engine runs rough or stutters when idling
• Increased fuel consumption: The engine control unit cannot regulate the injection optimally
• Poor engine performance: Loss of power and jerky engine running
• Overheating: In rare cases, the engine may overheat
• Black smoke: Incomplete combustion due to incorrect temperature values

How can the problem with fault code P0119 be rectified?

• Repairing fault code P0119 requires a systematic diagnosis of the coolant temperature components.
• Replace the coolant temperature sensor: Remove the faulty ECT sensor and install a new OEM sensor with the correct specification for your vehicle model
• Repair cable connections: Check all cables to the temperature sensor for damage and repair or replace defective cables completely
• Clean and secure plug connections: Clean the plug connections with contact spray and ensure that all connections are tight and corrosion-free
• Bleed the cooling system: Fill the cooling system properly and bleed it completely to remove air bubbles that can cause incorrect readings
• Replace thermostat: Replace a faulty thermostat that is causing erratic coolant temperatures
• Check engine control unit: Have the ECU tested by a professional and repaired or replaced if necessary