Computers and Control Systems: Service Precautions

1. Always disconnect battery ground cable before servicing or replacing electronic engine controls.
2. Follow diagnostic procedures.
3. Disconnect electronic engine controls from wire harness before measuring for resistance or energizing with a 12-volt source.
4. Never measure voltage or resistance directly at the Powertrain Control Module (PCM). Use Rotunda EEC-V 104-Pin Breakout Box 418-049 (014-00950) or equivalent.