OM4206 06/06 Maintenance - Section 42 Automatic Lubrication System Page 42-15 SYSTEM TROUBLESHOOTING CHART NOTE: If the following procedures do not correct the problem, contact a factory authorized service center. PROBLEM POSSIBLE CAUSES SUGGESTED CORRECTIVE ACTION Pump Does Not Operate. Lubrication system not grounded. Electrical power loss. Timer malfunction. Solenoid valve malfunctioning. Relay malfunctioning. Motor or pump malfunction. Correct grounding connections to pump assembly and truck chassis. Locate cause of power loss and repair. 24VDC power required. Ensure key switch is on. Replace timer assembly. Replace solenoid valve assembly. Replace relay.
Repair or replace motor and/or pump assembly. Refer to the Service manual for rebuild instructions. NOTE: On initial startup of the lubrication system, the timing capacitor will not contain a charge. Therefore, the first timing cycle will be about double in length compared to the normal interval. Subsequent timer cycles must be as specified. Pump Will Not Prime. Low lubricant supply. Dirt in reservoir, pump inlet clogged, filter clogged. Pump Will Not Build Pressure. Air trapped in lubricant supply line. Lubricant supply line leaking. Vent valve leaking. Pump worn or scored. Prime system to remove trapped air. Check lines and connections to repair leakage. Clean or replace vent valve.
Repair or replace pump assembly. Refer to the Service manual for rebuild instruc- tions. Injector Indicator Stem Does Not Operate. NOTE: During operation, the injector indicator stem will move into the body of the injector when pressure builds properly. When the system vents (pressure release), the indicator stem will again move out into the adjusting yoke. Malfunctioning injector - usually indicated by the pump building pressure and then venting. All injectors inoperative - pump build up not sufficient to cycle injec- tors. Replace individual injector assembly. Service and/or replace pump assembly. Refer to the Service manual for rebuild instructions.
Pressure Gauge Does Not Register Pressure. No system pressure to pump motor. No 24VDC signal at pump solenoid. Pressure reducing valve set too low. 24V Relay (RB7K8 or RB7K5) may be defective. Check hydraulic hose from steering sys- tem. Determine problem in 24VDC electric sys- tem. Refer to Pressure Control Valve Adjust- ment. Replace relay.