The Sealey VS925 is a professional lambda sensor tester designed for diagnosing both Zirconia and Titania oxygen sensors and ECU performance. This versatile diagnostic tool is suitable for use with 1, 2, 3 and 4-wire sensors, covering both heated and unheated configurations commonly found in modern vehicle emission systems. The tester features an LED display that clearly shows the crossover signal from the sensor, enabling technicians to quickly verify sensor operation. Its simulation capability allows testing of ECU response by generating rich or lean mixture signals, making it ideal for comprehensive engine management diagnostics and fault-finding in automotive workshops. Connection is straightforward thanks to the insulation-piercing clip which allows quick attachment without damaging wiring, whilst the integrated display confirms wire identity to prevent incorrect connections. The unit includes a low battery indicator to ensure reliable operation and is powered by a 9V battery whic