2002 Pontiac Grand Prix 3800 - P0102 OBD II Code: Mass Air Sensor Voltage Issue Diagnosis and Fix

I recently encountered OBD II diagnostic code P0102 on my 2002 Pontiac Grand Prix with a 3800 engine, which indicates a 'Mass Airflow Sensor Volume Air Low Voltage' fault. This means the mass air sensor (MAS) is sending an abnormally low or zero voltage signal to the Engine Control Module (ECM), suggesting a problem in its sensing circuit. After replacing the MAS with a new unit, I conducted detailed electrical testing and discovered key diagnostic insights. According to technical specifications from www.hhodevelopment.com/MAP.htm, a properly functioning mass air sensor on this vehicle should show: - 15 ohms between the DC voltage circuit and ground terminal (no power applied) - 15 ohms between the indicating circuit and ground terminal - A ground resistance of 3 ohms for the harness ground wire - A stable 13 volts DC at the harness when powered on My original sensor tested correctly on the DC circuit but showed 0 ohms (short to ground) in the indicating circuit, which indicates an open circuit. This is typically caused by internal wiring degradation due to heat generated during operation. After installing the new mass air sensor and verifying all electrical parameters matched specifications, the P0102 code cleared. I used an OBD II scanner to reset the MIL (Malfunction Indicator Lamp), as the system did not auto-reset. This repair confirms that a faulty indicating circuit in the mass airflow sensor—often due to internal wire failure—is a common cause of P010-2 on 2002 Pontiac Grand Prix 3800 models. The solution is straightforward: replace the sensor with a properly tested unit and verify electrical continuity before reinstallation. Thanks to earlier forum contributors who shared technical resources that helped me diagnose this issue effectively.