Proper Tools and Testing Procedures
DIGITAL VOLT/OHM METER
Use a Digital Volt-Ohm Meter (DVOM) with a minimum 10 mega-ohms internal impedance when testing an Electronic Control Module or related component, unless use of an analog meter is specified by a test procedure.
Analog meters have low internal impedance and will "load" low voltage circuits, resulting in inaccurate measurements and possible damage to components.
TESTING PROCEDURES
Always follow recommended testing procedures.
Never ground or apply voltage to a circuit, unless specified by a test procedure. Directly grounding or applying battery power to a circuit may damage the circuit and/or components.