GASKET 4N4188 - Caterpillar

Conditions Which Generate This Code: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 phase C connection 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.STOPTest Step 2. CHECK THE VOLTAGE OF THE INPUTS TO THE BUS TRANSFORMER BOX (BTB +)
Illustration 1 g00603288
Bus transformer box
Turn the engine control switch (ECS) to "STOP".
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.STOPTest Step 3. CHECK THE VOLTAGE ON THE OUTPUT OF THE BTB+.
Stop the engine. Turn the engine control switch (ECS) to "STOP".
Install cable probes on connector contacts 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 engergize the bus.
Measure the voltage between connector contacts 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 +. See Testing and Adjusting, "EMPC Electronic Control (Bus Transformer Box) - Replace".STOPTest Step 4. CHECK THE INPUT WIRES OF THE GSC+P FROM THE BTB +.
Stop the engine. Turn the engine control switch (ECS) to "STOP".
Locate the input wires on contact 17, and contact 18 of the GSC+P from the BTB