The 2019 Audi Q5's P0119 code indicates the ECU detected intermittent or erratic signals from the Engine Coolant Temperature sensor. Unlike consistent high or low codes, intermittent codes suggest connection problems that come and go—making diagnosis more challenging but pointing toward specific causes.
What P0119 Means
P0119 indicates the ECT signal is dropping out, spiking, or behaving erratically. The sensor may work correctly most of the time but periodically send incorrect data. This intermittent pattern typically points to loose connections, damaged wiring, or a sensor that's partially failing.
Audi Q5 Considerations
The 2019 Q5's 2.0L TFSI engine uses the ECT sensor for fuel calculations, fan control, and temperature display. Audi's sophisticated engine management cross-references multiple sensors, making it particularly good at detecting erratic readings. The connector's location near coolant makes it susceptible to moisture and corrosion.
Common Causes of Intermittent ECT Signals
Corroded or loose connectors cause most intermittent issues. The ECT connector may appear secure but have internal corrosion from coolant vapor or moisture. Contact resistance varies with temperature and vibration.
Damaged wiring that maintains contact most of the time but breaks under certain conditions causes intermittent signals. Heat cycling expands and contracts wire, potentially opening partial breaks.
A failing sensor may work intermittently as internal components degrade from thermal cycling over years of operation.
Diagnostic Strategy
Monitor ECT data continuously while manipulating the connector and wiring. Look for reading changes that correspond to wiggling or flexing. Drive while monitoring—note correlations between temperature gauge fluctuations and data anomalies. Inspect the connector carefully for corrosion, which may be inside pin sockets.