Electrical Load System
WARNING: This page is about a different car, the 1995 Mazda RX-7. However, it is still accessible from the selected car via links, so may be relevant.
CPU acts as an electrical load sensor. Remove CPU from right side kick panel above ECU. Check voltage at terminals of CPU connector. See CPU UNIT VOLTAGE CHART. See Fig 1 . If voltages are incorrect, check appropriate circuit. If circuits are okay but voltages are still incorrect, replace CPU.