The 2019 Hyundai Tucson's P0109 code indicates the ECU detected intermittent or erratic signals from the MAP sensor. Unlike consistent high or low codes, intermittent codes mean the problem comes and goes—making diagnosis more challenging but pointing toward connection or wiring issues.
What P0109 Indicates
P0109 means the MAP sensor 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.
Tucson Engine and Conditions
The 2019 Tucson uses either a 2.0L or 2.4L naturally aspirated engine. Engine vibration and temperature cycling over years can loosen connections or cause wire fatigue, leading to intermittent contact issues that cause P0109.
Common Causes of Intermittent MAP Signals
Loose or corroded connectors cause most intermittent issues. The connector may appear secure but have worn terminals or internal corrosion that loses contact under vibration. Heat cycling accelerates connector degradation.
Damaged wiring with partial internal breaks can maintain contact most of the time but disconnect momentarily. Flexing or vibration causes these intermittent open circuits.
A failing MAP sensor may work intermittently as internal components degrade. Temperature changes can cause borderline components to work or fail.
Diagnostic Strategy
Connect a scan tool and monitor MAP data continuously. While watching, wiggle the connector and gently flex the wiring to see if readings spike or drop out. Drive the vehicle while monitoring—note any correlation between symptoms (stumble, hesitation) and MAP data anomalies. The goal is catching the fault in action.