Engine Controls - Pin Voltage Charts: Introduction
Pin voltage charts and known-good wave patterns are supplied to reduce diagnostic time. Checking pin voltages at the Engine Control Module (ECM) harness connector determines whether it is receiving and transmitting proper voltage signals. Comparing wave patterns with known-good wave patterns will confirm proper signal. Diagnostic charts may also determine if harness is shorted or open.
NOTE:
Unless stated otherwise in testing procedures, perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance. Voltage readings may vary slightly due to battery condition or charging rate.