The Bus Transformer Box (BTB +) reduces the AC line to neutral voltages of phase A and phase C from the bus to usable signal levels for the GSC+P. The GSC+P uses these reduced signals for detecting the phase angle with the generator. The GSC+P also uses these reduced signals for detecting the phase sequence of the bus. The GSC+P will utilize the signal of phase A in order to measure the amplitude of the voltage on the bus. The GSC+P will utilize the signal of phase C in order to measure the frequency of the voltage on the bus.
The possible cause of a CID 1170 FMI 08 diagnostic code is an open connection from phase C to the input of the BTB +.
Test Step 1. CHECK THE BTB+ FUSES.
- Stop the engine by turning the Engine Control Switch (ECS) to STOP.
- Remove the two fuses from the BTB+.
- Measure the resistance of the fuses with a digital multimeter.
Expected Result:
The resistance should be less than 1.0 ohms.
Results:
- OK - The resistance is less than 1.0 ohms. The fuses have not failed. Install the fuses. Proceed to Test Step 2.
- NOT OK - The fuses are blown.
Repair: Replace the fuses.
STOP
Test Step 2. CHECK THE VOLTAGE OF THE INPUTS TO THE BUS TRANSFORMER BOX (BTB +)
- Turn the ECS to "STOP".
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| Illustration 1 | g00603288 |
Bus transformer box | |
- Locate the input wires of the BTB +.
- Start the engine and run the engine at rated speed.
- Close the breaker in order to energize the bus.
- Measure the voltage from phase A to phase C.
Expected Result:
The voltage should be the normal operating voltage.
Results:
- OK - The voltage is the normal operating voltage. Proceed to Test Step 3.
- NOT OK - The voltage is NOT the normal operating voltage.
Repair: There is no voltage on phase C. Use the System Schematic for the BTB + and the AC schematic in Testing And Adjusting, "Schematics And Wiring Diagrams" section to troubleshoot the wiring and find the exact cause of the diagnostic.
STOP
Test Step 3. CHECK THE VOLTAGE ON THE OUTPUT OF THE BTB+.
- Stop the engine. Turn the ECS to "STOP".
- Install cable probes on connector pins A and B of three terminal connector "J1" on the BTB+.
- Start the engine and run the engine at rated speed.
- Close the breaker in order to energize the bus.
- Measure the voltage between connector pins A and B of "J1".
Expected Result:
The voltage should be equal to the voltage measured in Test Step 2 divided by 15 ± 2% (14.7 to 15.3).
Results:
- OK - The voltage is correct. Proceed to Test Step 4.
- NOT OK - The voltage is NOT correct. The BTB+ has failed.
Repair: The BTB + has failed. Replace the BTB +. Refer to Testing and Adjusting, "EMPC Electronic Control (Bus Transformer Box) - Replace".
STOP
Test Step 4. CHECK THE INPUT WIRES OF THE GSC+P FROM THE BTB +.
- Stop the engine. Turn the ECS to "STOP".
- Locate the input wires on pin 17, and pin 18 of the GSC+P from the BTB +. Install cable probes on these pins.
- Start the engine and run the engine at rated speed.
- Close the breaker in order to energize the bus.
- Measure the voltage between the GSC+P connector pin 17 and pin 18.
Expected Result:
The voltage should be equal to the voltage measured in Test Step 2 divided by 15 ± 2% (14.7 to 15.3).
Results:
- OK - The voltage is correct. CID 1170 FMI 2 is still active.
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
- NOT OK - The voltage is not correct. The wiring harness has failed between the BTB + and the generator.
Repair: The wiring harness has failed between the BTB + and the generator. Repair the wiring harness or replace the wiring harness. Use the System Schematic for the BTB + and the AC schematic in the Testing And Adjusting, "Schematics And Wiring Diagrams" section.
STOP