Circuit/System Testing

Without RPO UAV

1. Ignition OFF, disconnect the harness connector at the cellular microphone.
2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal A and ground.
   • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the VCIM.
3. Ignition ON, test for 9-11 volts between the signal circuit terminal B and ground.
   • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the VCIM.
   • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the VCIM.
4. If all circuits test normal, test or replace the cellular microphone.

With RPO UAV

1. Ignition OFF, disconnect the X4 harness connector at the navigation radio and the harness connector at the cellular microphone.
2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal A and ground.
   • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the VCIM.
3. Ignition ON, test for 9-11 volts between the signal circuit terminal B and ground.
   • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the VCIM.
   • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the VCIM.
4. If all circuits test normal, test or replace the cellular microphone.
5. Connect the X4 harness connector at the navigation radio. Verify DTC B2455 is not set as current in the navigation radio.
   • If DTC B2455 is set as current, replace the navigation radio.