Proper Tools and Testing Procedures

SCAN TOOLS
Not all scan testers are compatible with every system. A scan tool that produces faulty readings should NOT be used, and the problem should be reported to the tool manufacturer. Use of a faulty scan tool can result in improper diagnosis and unnecessary component replacement. Follow the proper instructions, located in the owners manual, for the specific scan tool being used.

DIGITAL VOLT / OHM METER
Use a digital volt / ohm meter (DVOM) with a minimum 10 megohms internal impedance when testing a Control Module or related components, unless use of an analog meter is specified by a testing procedure. Analog meters have low internal impedance and cause circuit "loading" in low voltage circuits, resulting in inaccurate measurements and possible damage to components. Use of a DVOM is necessary to obtain accurate measurements and avoid damaging low voltage Control Module circuits and components.

TESTING PROCEDURES
Always follow recommended testing procedures. Never ground or apply voltage to a circuit unless specified by a testing procedure. The Control Module provides a regulated constant low voltage source to some circuits, which may require a minimum resistance (impedance) to operate. Directly grounding or applying battery power to these circuits could damage the Control Module and cause a system failure.