ECU - Testing Precautions
Group: ENGINE ELECTRICALNumber: 92-36-005
Date: DECEMBER, 1992
Model: ALL
Subject:
ECU TESTING PRECAUTIONS
This bulletin is issued to remind Hyundai technicians NOT to use a test light when checking computer controlled circuits. Use a Digital Volt-Ohm Meter (DVOM) whenever checking the voltage in any computer controlled circuit. Never use a test light to check any computer circuit.
Electronic Control Units that have been replaced under warranty and returned for analysis usually have burnt transistors. Burned transistors are usually caused by high current demands when a test light is utilized to check for voltage in computer circuits. Test light bulbs draw a considerable amount of current in order to light. In most cases, the current demands of a test light will overload the solid-state components (transistors) causing damage.
A DVOM (Digital Volt-Ohm Meter) is the method preferred and recommended by Hyundai for use in the testing of computer circuits. However, Light Emitting Diode (L.E.D.) Testers (logic probe) or lab type oscilloscope may be used to perform some tests as these devices draw small amounts of current through the circuit being tested.