Engine System, Diesel 89Service Manual – SW8000Engine Overheating ProblemsWhen the Coolant Temperature Switch S8 senses that the coolant temperature is too high, it grounds outthe wire to the MIL INPUT J2-5 input on the A2 Main Machine Controller. The A2 Main Machine Controllerthen lights the Engine Service Indicator light on the control panel.Use the checklist below as a guide to thoroughly check the engine cooling system.• Check the coolant level in the overflow tank and radiator.• Inspect and clean the radiator and hydraulic oil cooler.• Check for correct operation of the belt-driven engine cooling fan (slippage).• Check to see that the engine thermostat opens.• Check for correct water pump operation.• Check the engine crankcase oil level.• Check for air trapped in the cooling system. (Refer to the Engine Coolant/Replacing Engine Coolantsection.)• Check the coolant temperature switch for correct function as replace if necessary.Loss of Oil PressureCheck for possible causes for low oil pressure such as:• Engine crankcase level is low.• Incorrect oil viscosity.• Fault in the oil pressure switch S28.• Excessive engine wear or defective internal oil pump (relief valve)APECS 3000 Controller Fault CodesThe Woodward APECS 3000 Controller is capable of identifying some fault conditions and displaying a faultcode. A flashing LED displays the fault conditions. When power is first applied to the Controller, the LEDwill flash just once for one second to indicate that the LED is operational. If there is more than one fault, theLED will flash them all. If there are no faults the LED will flash once every reset, and from then on indicatethe detection of engine speed. The controller will attempt to shut the engine down for all faults and will notpermit starting after reset with fault 1, 5 and 6.FlashCode Fault Correction1 APECS unit not calibrated. Calibrate the unit.2 Excessive engine speed. Check parameter settings, wiring, case ground, linkage andspeed sensor.3 Unusually low engine speed. Check parameter settings, linkage, load and engine capacity.4 Protection input shuts down engine. Check parameter settings and probable cause for fault.5 Factory settings lost. Download calibration file and recycle power or consultfactory.6 APECS unit failed. Check wiring, shielding, and recycle power. Consult factory.
