SCC Fault Isolation Manual 6/03/2020
Page 9 of 11 Rev. 01 9/20/2021
1. Display does not turn on
1.1. Go to the primary PLC. Is the PLC lit-up?
1.1.1. NO: Go to page 10 section 10. System does not turn on
1.1.2. YES: Check the connection behind the display to ensure it is seated properly. Then check fuse F18. If both are good replace display or check for power/ground at the connector. The display must be
programmed before shipping and it must be compatible with the PLC version. To find the PLC version when the display does not work, refer to the Work Instruction: “SCT Program - Finding Correct SCT
Version”
2. Primary PLC does not turn on (No lights on PLC)
2.1. Does the display turn on?
2.1.1. NO: Go to page 10 section 10. System does not turn on
2.1.2. YES: Check fuse F2 in the PDM then check both connectors for proper connection at the PLC and that it has no loose pins. Is there 12v on pins 10 and 32 and grounds on 20, 37 and 42 on ST Connector?
(Vehicle Ignition must be on)
2.1.2.1. NO: Use the system schematic to trace power back into the PDM and check the F2 circuit breaker.
2.1.2.2. YES: Replace PLC
3. Throttle control does not work
3.1. The E-Stops must be cleared and no errors/messages should be shown on the screen for throttle to work. On the SCT display, go to the I/O screen. Have someone request throttle up and down while watching
outputs 23ex (RPM+) and 22ex (RPM-). Do both outputs light up at the appropriate time?
3.1.1. NO: The system is not allowing throttle control. Check to make sure your e-stops are clear and you are properly setup.
3.1.2. YES: The system is requesting the vehicle to throttle up and down but it is not. The issue is either with the vehicle or with the harness between the vehicle and the CPC3 system.
4. Oil Cooler does not turn on
The Oil Cooler shuts off if the D+ signal from the alternator is lost. It can still be controlled manually.
If the PLC supply voltage drops below 11V for 10 seconds, the oil cooler will be disabled. Connect Jumper cables and charge batteries.
4.1. The oil cooler will turn on automatically when the temperature reaches 55°c, the engine is running and the E-Stop is cleared. You can also turn it on manually by the rear panel.
4.1.1. Go to the display and navigate to the I/O pages then check if OUT30ex (Oil Cooler) is coming on.
4.1.1.1. YES: Check the oil cooler Fuse F8. If the fuse is good, check for power and ground at the oil cooler connector.
4.1.1.2. NO: The system is not telling the oil cooler to come on. Either oil temp is not above 55° or the system believes the truck is not running. Check input 06ex (Vehicle D+). The input should be on when the vehicle is running. Is the input
on?
4.1.1.2.1. YES: Call Schwing Service Tech.
4.1.1.2.2. NO: Trace the D+ circuit from the vehicle alternator.
5. Slew Limits do not work
5.1. The slew limits are set mechanically inside the Slew Gear. Check F20 fuse in the PDM. Check that the slew counter is properly set, then trace the wires using the schematic (Inputs 08 and 09).
6. Fuse F9 blows while in maintenance mode
6.1. There is a wire with a quick disconnect located near connector “Cable C” under the control cabinet faceplate. Disconnect the quick disconnect and reset the circuit breaker. Does the circuit breaker still pop?
6.1.1. NO: Leave the quick disconnect disconnected and tape over both ends.
6.1.2. YES: There is a short in the system. Use the schematic and find the short on the “Maintenance Splits Diode Pack” (PMSD).
To Next Page
Loading...
Need help?
General