The circuit breaker sensor is used by the GSC+P to determine if the generator circuit is opened or closed. When the circuit breaker sensor input is inactive the input will float to approximately 10.5 DCV. An inactive state will indicate that the circuit breaker is open. When the circuit breaker sensor input is active, the voltage level will be at the level of the negative battery terminal "BATT-". An active state indicates that the breaker is closed.
The possible cause of a CID 1167 FMI 4 is a short from the input signal of the circuit breaker sensor to "BATT-".
A CID 1167 FMI 04 is detected when the input of the circuit breaker sensor is active. The CID 1167 FMI 04 indicates a closed breaker and one or both of the following items are true.
- The difference of frequency between the generator and the bus is greater than 0.2 Hz.
- The difference of phase between the generator and the bus is greater than 10°.
When the above conditions are present for two seconds, the GSC+P will issue a CID 1167 FMI 4 as an alarm fault. The GSC+P will then stop the synchronization process until the diagnostic code is cleared and the diagnostic code is corrected.
Test Step 1. CHECK THE INACTIVE VOLTAGE LEVEL OF THE CIRCUIT BREAKER SENSOR.
- Turn the Engine Control Switch (ECS) to STOP.
- Locate the wire that is connecting pin 25 of the GSC+P to the terminal CBR-9 of the Circuit Breaker relay (CBR). Remove this wire at terminal CBR-9 of the Circuit Breaker Relay (CBR) only. Pin 25 of GSC+P will remain connected to the wire.
- Use a cable probe to measure the voltage at pin 25 of the GSC+P.
Expected Result:
The voltage should measure 10.5 ± 1 DCV.
Results:
- OK - The voltage is 10.5 ± 1 DCV. Proceed to Test Step 2.
- NOT OK - The voltage is not within the correct range.
Repair: The GSC+P may have failed. It is unlikely that the GSC+P has failed. Exit this procedure and perform this entire procedure again. If the problem remains, replace the GSC+P. Refer to Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace".
STOP
Test Step 2. CHECK THE FUNCTION OF THE INPUT OF THE CIRCUIT BREAKER SENSOR.
- The wire that is connecting pin 25 of the GSC+P and terminal CBR-9 of the Circuit Breaker relay (CBR) remains disconnected.
- Start the engine. Adjust the engine speed so the generator frequency is more than 0.2 Hz of the frequency of the bus.
- Perform the Manual paralleling function. Refer to Systems Operation, "Synchronization Sequence Of Operation".
- Ensure that the synchroscope is present on the lower display of the GSC+P.
- Touch the loose end of the wire of pin 25 of the GSC+P to "BATT-".
Expected Result:
After two seconds, the CID 1167 FMI 4 should be active.
Results:
- OK - The GSC+P issues the diagnostic.
Repair: The GSC+P is operating correctly, and the problem is in the wiring or the component that is connected to the input of the circuit breaker sensor. Use the FMI information and use the Close Breaker Input System Schematic to find the exact cause of the diagnostic code.
STOP
- NOT OK - The GSC+P does not issue the diagnostic.
Repair: The GSC+P has failed. Replace the GSC+P. Refer to Testing and Adjusting, "EMPC Electronic Control (Generator Set) - Replace".
STOP