INTRODUCTION
Pin voltage charts are supplied to reduce diagnostic time. Checking pin voltages at the ECM determines whether it is receiving and transmitting proper voltage signals. Charts may also help determine if ECM harness is open or shorted.
Note. Unless stated otherwise in testing procedures, perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a 10-megohm input impedance. Voltage readings may vary slightly due to battery condition or charging rate.
TESTING
- ECM circuits are checked at ECM connectors. (Scheme 1), (Scheme 2), (Scheme 3) and (Scheme 4). Testing may be performed with ignition off, with ignition on and engine off, and/or with ignition on and engine running. Test between indicated terminal and good body ground. (Scheme 5)- (Scheme 18). When testing pin voltage, carefully backprobe terminal at harness side of ECM connector.
- If voltage is not as specified, test, repair or replace circuit or affected component. Retest circuit to verify repair has been made. Unless stated otherwise, perform all tests with ECM harness connected.
