PLUG 6E3653 - Caterpillar

Table 1
Related Service Manuals
Title Form Number
M Series Motor Grader Service Manual RENR 9030
14M Power Train Electrical Control System RENR 9004
14M Implement and Steering Hydraulic System RENR 8484
Motor Graders Monitoring System RENR 9034
Additional References
14M Electrical System Schematic RENR 9023
14M Hydraulic System Schematic RENR 9028
Accugrade GPS System For Motor Graders SEBU 8003
Accugrade Laser System For Motor Graders SEBU 8276 As a reference, a simplified implement electrical system schematic is included at the end of this manual. For a complete representation of the machine that is being diagnosed, refer to the Electrical System Schematic in the Service Manual of the machine.When the troubleshooting procedure instructs you to “REPAIR THE HARNESS OR REPLACE THE HARNESS”, use the Electrical System Schematic in the Service Manual of the machine to trace the circuit. Perform resistance checks at the harness connectors to locate harness failures. Always check the ground circuit at the machine harness connector for the components. Less than five ohms of resistance is required between the ground contacts of the connector and the frame ground. Excessive ground resistance that is greater than five ohms can cause an incorrect diagnosis of the system.During troubleshooting, inspect all harness connections before any component is replaced. If these connections are not clean and tight, permanent electrical problems or intermittent electrical problems can result. Check that the wires are pushed into the connectors completely. Make sure that the connections are tight before other tests are made.Failure of an electrical component can cause the failure of other components. Always attempt to correct the cause of an electrical system failure before you replace a component. If wire insulation is punctured during troubleshooting, repair the damage. Seal the damaged wires with 8T-0065 RTV Silicone Sealant. Cover the sealant with two layers of 1P-0810 Electrical TapeECM Pull Up Voltage
To aid in diagnostics of certain types of electrical circuits that are controlled by the ECM, an internal "pull up voltage" is connected to ECM switch and sensor signal input contacts. An above normal voltage is internally connected to the ECM signal input circuit through a resister.During normal operation, the switch or sensor signal will hold the circuit low or at a certain signal amplitude, however, circuit conditions such as a loss of power to the component, a disconnection or an open circuit will allow the circuit to be pulled high by the ECM pull up voltage. This will result in an above normal voltage condition at the ECM contact. As a result, the ECM will activate an FMI 03 (voltage above normal) diagnostic code for the affected circuit.The types of ECM input circuits that have pull-up voltage present are:
Pulse Width Modulated (PWM) sensor input circuits
Switch to ground switch input circuits
Active analog (voltage) input signal circuits
Passive analog (resistance) input signal circuitsThe ECM pull-up voltage should always be considered when troubleshooting one of the circuit types that are listed.ECM Pull Down Voltage
To aid in diagnostics of electrical circuits that are controlled by the ECM, an internal "pull down voltage" is connected to ECM