Engine Controls - Pin Voltage Charts: Introduction
Pin voltage charts are supplied to reduce diagnostic time. By checking pin voltages at the Electronic Control Module (ECM), it is possible to determine if the ECM is receiving and transmitting proper voltage signals. Charts may also help determine if ECM harness has shorts or opens.
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. Voltage readings may vary slightly due to battery condition or charging rate.
NOTE:
The following conditions must be met before testing:
- Engine at operating temperature.
- At idle in closed loop operating mode (engine running tests).
- ALDL diagnostic connector is NOT grounded.
- Scan tester is NOT installed.