x10: Code 72 or 78: Intermittent Open in VPWR Circuit
| Steps | Possible Causes:
_Intermittent open in VPWR circuit from Integrated Controller to processor _EEC power relay intermittent malfunction _Intermittent open in VBATT circuit to Integrated Controller _Intermittent open in KEY POWER circuit to Integrated Controller _EEC harness too close to the distributor spark plug wires and other vehicle harnesses _Using Continuous Monitor Mode (Engine Running) per Appendix in Section 16, observe VOM or STAR LED for indication of a fault while performing the following: _Shake, bend and twist harness from Integrated Controller to the processor, to the ignition switch and to battery positive. |
| Result | Is a fault indicated or does Code 72 or 78 reappear in Continuous Memory if Quick Test is rerun? |
| Direction | YES
Check for proper routing of EEC harness. Service as necessary. If OK, service intermittent VPWR circuit. Rerun Quick Test. NO Inspect component and harness connectors of Integrated Controller and processor for loose or damaged pins, corrosion, etc. Service as necessary. If OK, road test vehicle through a variety of drive modes. If symptom exists, replace Integrated Controller, otherwise testing complete. Rerun Quick Test. |
| Notes | Code 72 or 78 indicates that while key power was present, VPWR had an interrupt, or interference from electrical noises caused the processor to reset, resulting in possible stalls, high idle rpm, lack of power on acceleration or other drive symptoms. |