Table 2-1. Troubleshooting - Continued
TEST OR INSPECTION
Figure 2-58. Removal of electronic control unit assembly.
If the system operates correctly with the new ECU, report the bad ECU to the next higher level of main-
Step 3. Check for a defective GRU.
Replace existing GRU with a GRU that is operable, by disconnecting and connecting power cables (fig. 2-59).
Figure 2-59. Gyroscopic reference unit power cable removal.
If the system operates correctly with the new GRU, report the bad GRU to the next
higher level of maintenance.
10. RESET CIRCUIT INOPERATIVE WHEN RESET SWITCH IS PRESSED
Step 2. Check for defective RESET switch (2A2S5).
a. Loosen the eight captive screws and lift the electronic control panel assembly from the case (fig. 2-24).