SEAL 4777578 - Caterpillar

Table 1
Diagnostic Trouble Codes
J1939 Code Code Description Comments
1485-7 ECM Main Relay : Not Responding Properly The Electronic Control Module (ECM) detects that the battery supply voltage is still present 0.5 seconds after the shut-off request from the ECM.
The warning lamp will come on.
The ECM is receiving battery voltage after the keyswitch has been turned OFF, which will drain battery power.
1485-14 ECM Main relay : Special Instruction The ECM requires battery voltage for up to 60 seconds after the keyswitch has been turned OFF.
A fault is caused when the ECM has lost battery voltage before this period has elapsed.
The fault is detected the next time the keyswitch is turned ON. The diagnostic code becomes active when the fault is detected for three consecutive starts.
The warning lamp will come on.
This condition is most likely caused by shutting the engine down using the battery disconnect switch instead of the keyswitch for three consecutive shutdowns or using the battery disconnect switch immediately after the keyswitch has been turned OFF.
2840-14 ECU Instance : Special Instruction The ECM was unable to write data to the internal memory.
This condition is most likely caused by removing battery power from the ECM while the ECM was attempting to write data to the internal memory.
Follow the troubleshooting procedure in order to identify the root cause of the problem.
Illustration 1 g03729651
Schematic diagram for the ECM main relay
Not all connectors are shown. Refer to the Electrical Schematic for the application.
Illustration 2 g02716384
View of the pin locations on the P1 connector for the ignition keyswitch and battery supply circuit
(1) Battery+
(2) Battery ground
(3) Battery+
(4) Battery ground
(5) Battery+
(6) Battery ground
(28) ECM main relay
(54) Ignition key switch
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Check the fuses.
B. Thoroughly inspect the P1/J1 ECM connectors and thoroughly inspect the connector for the ECM main relay. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 30 N (6.7 lb) pull test on each of the wires that are associated with the main relay.
Damaged wire or connector
Result: A damaged wire or damaged connector was not found. The fuses are OK.
Proceed to Test Step 2.
Result: A damaged wire or damaged connector was found. A fuse is blown.
Repair: Repair the damaged wire or the damaged connector. Replace any blown fuses.
Use the electronic service tool to clear all logged diagnostic codes. Verify that the repair eliminates the fault.
2. Check for Diagnostic Codes
A. Turn the keyswitch to the OFF position.
B. Connect the electronic service tool to the diagnostic connector.
C. Turn the keyswitch to the ON position.
D. Monitor the electronic service tool for active diagnostic codes and/or logged diagnostic codes.
Diagnostic Trouble Codes
Result: A 1485-7 diagnostic code is active or recently logged.
Proceed to Test Step 3.
Result: A 1485-14 or 2840-14 diagnostic code is active or recently logged.
Repair: Ensure that the correct procedure is used to shut down the engine. Refer to Operation and Maintenance Manual, "Stopping the Engine".
If the engine is being shut down correctly, an intermittent fault may be causing the ECM to lose battery power. Refer to Troubleshooting, "Electrical