Engine Controls - Pin Voltage Charts: Introduction

PIN VOLTAGE CHARTS are supplied (when available) to reduce diagnostic time. Checking pin voltages at the electronic control unit determines if it is receiving and transmitting proper signals. Charts may also help determine if control unit harness is shorted or open.

NOTE: All voltage tests should be performed with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in testing procedures.

NOTE: This ECM voltage chart along with digital voltmeter can help save diagnosis time. Voltage readings may vary slightly depending on battery voltage and alternator output.

CAUTION: The following conditions must be met before testing:

Engine at operating temperature.
Engine in closed loop operation.
Engine idling (Engine Run column).
ALDL "test" terminal NOT grounded.
Scan tester NOT installed.