ENGINE AR-PRIM 20R3530 - Caterpillar

Table 1
Diagnostic Trouble Codes for the Start Relay
J1939 Code and Description Comments
677-5
Starter Motor Relay : Current Below Normal The Electronic Control Module (ECM) detects a low current condition (open circuit) in the start relay control circuit.
677-6
Starter Motor Relay : Current Above Normal The Electronic Control Module (ECM) detects a high current condition (short circuit) in the start relay control circuit.
Follow the troubleshooting procedure in order to identify the root cause of the fault.
Table 2
Component Electrical Checkout
Engine Starter Motor Relay Attempt to start the engine. Once the ECM attempts to energize the relay, the code will become active. Refer to the machine-specific schematic for the "Engine Starter Motor Relay" wiring circuit. During the following procedure, refer to the electrical schematic for the application.Complete the procedure in the order in which the steps are listed.
Table 3
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Check that the fuses are not blown.
B. Inspect the terminals on the start relay. Refer to Troubleshooting, "Electrical Connector - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the start relay.
D. Check the screw for the ECM connector for the correct torque of 6 N m (53 lb in).
E. Check the harness for abrasion and pinch points from the start relay back to the ECM.
Loose connection or damaged wire
Result: There is a fault in a connector or the wiring.
Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all of the seals are properly in place and ensure that the connectors are correctly coupled.
Replace any blown fuses.
Use the electronic service tool to clear all logged diagnostic codes and verify that the