PLUNGER AND BARREL ASSEM. 9H5797 - Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the engine starting system. Also, use this procedure if one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table
J1939 Code and Description Conditions which Generate this Code System Response
677-5 Engine Starter Motor Relay : Current Below Normal The engine Electronic Control Module (ECM) detects an open in the circuit for the starter relay.
The ECM detects a short to battery voltage in the circuit for the starter relay.
The ECM can only detect this condition when the output driver is not activated. The code is logged.
677-6 Engine Starter Motor Relay : Current Above Normal The ECM detects a short in the circuit for the starter relay.
The ECM can only detect this condition when the output driver is activated. Use this procedure to troubleshoot the electrical system if a problem is suspected with the starting system.The ECM is provided with the ability to begin the engine cranking at any time after the ECM has received keyswitch power. The ECM receives the start command via the global CAN data link. Once this request is received, the engine is placed into the "Prestart State" of the control for the engine state. If the engine is equipped with a prelubrication system, the engine will wait until the prelube cycle has been completed before initiating engine cranking.Configuration ParametersThe settings of the following configuration parameters control engine starting:
Starting System #1 Maximum Number of Crank Cycles
Starting System #1 Crank Duration
Crank Terminate RPMConfiguration parameters for Starting System #2 are also available. Refer to Troubleshooting, "Configuration Parameters" for information that is related to these parameters.
Illustration 1 g02987576
Schematic for the engine starting system
There are also configuration parameters that are used to configure the ECM for the type and the location of the starting motors. The following types of starting motors can be used on this engine:
Air starting motor
Electric starting motorThe wiring for each of these types of engine starting circuits is similar. Follow this procedure in order to troubleshoot the circuit diagnostics for any of these types of engine starting system.The ECM can control a secondary starting system that is installed on the engine opposite the primary starting system. Refer to Troubleshooting, "Configuration Parameters" for information that is related to the configuration parameters that are for the secondary starting system.ECM Activation of the Starting MotorsThe ECM utilizes two output drivers in order to crank the engine. Each output driver is provided with 24 VDC during engine cranking. The circuits for the output drivers utilize a return line to the ECM. This circuit includes crank relays that can be powered by an external power supply in order to override the ECM activation of the starting motors.Manual Overrides for the Engine Starting SystemThe engine can be manually cranked by using a manual crank switch that can be wired into the engine interface connector. The engine starting circuit incorporates four crank relays. When the relay coils are powered by 24 VDC, the starting motor