0210273 JOHNSON OWNER'S MANUAL

Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
677-5 Engine Starter Motor Relay : Current Below Normal The Electronic Control Module (ECM) detects an open circuit and/or a short to the +Battery in the circuit for the Starter Motor Magnetic Switch (SMMS). The ECM can only detect this condition when the SMMS is not energized. The code is logged.
677-6 Engine Starter Motor Relay : Current Above Normal The ECM detects a short circuit to ground in the circuit for the SMMS. The ECM can only detect this condition when the SMMS is energized. The engine control system controls all aspects of engine start and stop functionality. In order to crank the engine, the ECM sends a signal to the Starting Motor Magnetic Switch (SMMS). Current will flow to the starting motor through the contacts of the SMMS. The starting motor will begin to crank the engine.The ECM receives a request to crank the engine over the CAN data link from the Electronic Modular Control Panel 3 (EMCP). Ensure that the "Engine State Control Input Configuration" is configured to "CAN Input" if an EMCP is installed on the engine.If the "Engine State Control Input Configuration" parameter is configured to "Hardwired", a switch input will be used by the ECM for engine starting. The switch must be wired to terminal location 40 at the J1/P1 ECM connector. Table defines the functionality of the switch input.
Table 2
ECM Switch Input Switch Input Engine State
P1/J1-40 −Battery Start/Run
P1/J1-40 +Battery Stop Refer to Troubleshooting, "Configuration Parameters".The ECM will crank the engine until the programmed "Crank Terminate RPM" has been reached. If the engine fails to reach the "Crank Terminate RPM" before the programmed "Crank Duration" period, the ECM will stop cranking the engine. The ECM will then allow the starter to cool for a period that is equal to the "Crank Duration" before starting the next crank cycle. The process will be repeated for a number of times that is equal to the programmed "Maximum Number of Crank Cycles". When the "Maximum Number of Crank Cycles" has been reached, the process will be aborted and Caterpillar Electronic Technician (ET) will display "OVERCRANK". The process will be restarted when the next start request is received by the ECM.Refer to Troubleshooting, "Configuration Parameters" for the available ranges and default settings of the following parameters:
"Crank Duration"
"Crank Terminate RPM"
"Maximum Number of Crank Cycles"Note: If the "Crank Duration" or "Maximum Number of Crank Cycles" are programmed to 0, the ECM will not crank the engine.
Illustration 1 g02175710
Schematic for the starting circuit
Test Step 1. Inspect Electrical Connectors and Wiring
Remove electrical power from the ECM.
Illustration 2 g02164341
Location of ECM connectors
(1) P1/J1
Thoroughly inspect the ECM connectors. Inspect all of the other connectors for the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g02175714
Terminal locations at the P1 ECM connector for the starting circuit
(43) SMMS driver
(51) SMMS driver
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and the wiring for abrasion and for pinch points. Expected Result:All connectors, pins, and sockets are coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The connectors and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes for the SMMS
Connect Cat ET to the service tool connector.
Restore electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET. Check for an active -5 diagnostic code for the SMMS. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the override for the starting system.
Monitor the active diagnostic code screen on Cat ET. Check for a -6 diagnostic code for the SMMS. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Deactivate the override for the starting system. Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active, but a problem is suspected in the starting system. Proceed to Test Step 6.
Not OK - A -6 diagnostic code is active at this time. Proceed to Test Step 3.
Not OK - A -5 diagnostic code is active at this time. Proceed to Test Step 4.Test Step 3. Create an Open at the Coil of the SMMS
Disconnect the wires from terminal 1 and terminal 2 on the SMMS or disconnect the connectors for the SMMS, if equipped. Ensure that the wires are isolated from engine ground and from sources of electrical power.
Monitor the active diagnostic code screen on Cat ET. Check for a -5 diagnostic code for the SMMS. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the override for the starting system.
Monitor the active diagnostic code screen on Cat ET. Check for a -6 diagnostic code for the SMMS. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Deactivate the override for the starting system. Expected Result:A -5 diagnostic code is now active for the starting motor system.Results:
OK - A -5 diagnostic code became active after creating the open at the SMMS. The wires from the ECM to the SMMS are OK.Repair: The problem may be in the coil of the SMMS. Install a new SMMS. Clear any logged diagnostic codes.STOP
Not OK - A -6 diagnostic code remains active. There is a short between the SMMS and the ECM. Leave the wires for the SMMS disconnected. Proceed to Test Step 5.Test Step 4. Create a Short at the Coil