Troubleshooting Tips


Cummins Issues:

We will need the following Information to assist with Cummins diagnostics:
  • Last 8 digits of the VIN number
  • Mileage
  • Engine Serial #.

Other Issues:

Bus will not start
  1. Check to be sure the back door is not locked/latched. The vandal lock system will not allow the bus to start.
  2. Go outside the bus under the driver’s window, look on the right side of the panel opening for a white connector “P5”. Disconnect this connector. This will isolate the vandal lock circuit from that point to the rear of the bus. If the bus starts, there is a short to ground in the body harness above the student windows on the driver side. Possible bad switch at the back-door latch. (You may run the bus like this but be sure you re-connect “P5” before you leave, this also controls all the lights on the rear of the bus.
  3. In the same fuse panel, look at the bottom left corner and unplug all 3 connectors of the body module. Try to start bus. Same thing the bus can be driven like this but make sure you reconnect the module so all the lights work as they should.
  4. Inside the bus, remove the black cover under the dash “Multiplex Cover” and Call in to our Service team and we can assist you in further diagnosis.

A/C systems not cooling properly
  1. Check the intake filters of both units for excessive dust/dirt build up
  2. Be sure the temperature knobs are both turned to cold
  3. Check to make sure all condenser fans are intact and working as they should
  4. Open the hood and check for proper belt installation
  5. If your system has a fuse panel on the driver side of the bus, check for tripped circuit breakers inside this panel.

Radio, fans, defrost, A/C, ect. Inop
  1. Check to make sure the yellow “Noise Suppression” switch is not depressed
  2. Under the driver’s window, look to the top left and check for power on both sides of the “Noise Suppression” solenoid.
  3. If there is no power on the bottom stud of the solenoid, check to be sure the solenoid is getting adequate supply and return to it on the control harness.

Trouble codes on the dash (Engine, ABS, Transmission)
  1. Set parking brake
  2. 2 button dash – Hold the bottom button down

3 button dash – Hold all 3 buttons down
  1. Scroll down to the diagnostics needed
  2. Write down fault codes be sure to include all numbers.
  3. Call in to our Service team and we can assist you in further diagnosis.

Sleeping Child Alarm
  1. If bus is equipped with a sleeping child alarm, there will be a chrome button on the rear wall on the Driver side.  Put this button each time you turn the bus off and go to exit the bus.  If this button is not pressed, do the following:
    1. Make sure the SL master switch is in the off position
    2. Close the entrance door
    3. Cut the switch to the engine to the off position
    4. Push the chrome button on the rear wall
    5. Immediately return to the front door, flip the door lever to open, and push the door open. 

Range Inhibiter (Bus will not come out or go into gear)
  1. Make sure your foot is on the brake when you put the bus in gear or the bus will not move, and the reange inhibitor light will come on. 
  2. Make sure the bus door is closed.
  3. Make sure the rear stop lights are working
    1. The fuse might be blown, located outside under driver’s window in fuse panel box.

Emergency window and door buzzers
  1. If you hear a dull buzzing noise coming out of the left driver panel, try opening and closing each emergency window, roof hatch, driver compartment over the driver seat, wheelchair doors, locks and rear entrance door. 

High Temp Exhaust Warning
  1. This is normal.  It just means the unit is regenerating the exhaust on its own.  Pull over and allow the bus exhaust to cool down. 

  1. If your bus is not generating heat, check the following items
    1. Is the heater valve handle by driver’s left foot turned to the on position?
    2. Are the 2 heater valves located in the engine turned to the on position | 1 yellow and 1 red – follow the hoses off of the radiator to locate heater valves on engine