SEAL-O-RING 3P5859 - Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with a sensor supply. Also, use this procedure if any one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
J1939 Code and Description Comments
678-3
ECU 8 Volts DC Supply : Voltage Above Normal The digital sensor supply voltage is above normal for two seconds.
The code is logged.
678-4
ECU 8 Volts DC Supply : Voltage Below Normal The digital sensor supply voltage is below normal for two seconds.
The code is logged.
3509-3
Sensor Supply Voltage 1 : Voltage Above Normal The analog sensor supply voltage is above normal for two seconds.
The code is logged.
3509-4
Sensor Supply Voltage 1 : Voltage Below Normal The analog sensor supply voltage is below normal for two seconds.
The code is logged.
3510-3
Sensor Supply Voltage 2 : Voltage Above Normal The analog sensor supply voltage is above normal for two seconds.
The code is logged.
3510-4
Sensor Supply Voltage 2 : Voltage Below Normal The analog sensor supply voltage is below normal for two seconds.
The code is logged. System OperationThe ECM supplies a regulated voltage of 8.0 0.4 VDC to the digital sensors.The ECM supplies a regulated voltage of 5.0 0.2 VDC to the analog sensors.The supply voltage for the sensors is routed from the ECM to terminal 1 of each sensor connector. The sensor return for the sensors is routed from the ECM to terminal 2 of each sensor connector. The ECM provides short circuit protection for the internal power supply. A short circuit to the battery will not damage the internal power supply.Note: The sensors are not protected from overvoltage. A short from the supply line to the +Battery may damage the sensors. Repair the sensor supply and check for any active sensor diagnostic codes to determine if a sensor has failed.
Illustration 1 g06120200
For the complete circuit details, refer to the full schematic.
Illustration 2 g06120236
For the complete circuit details, refer to the full schematic.
Table 2
Troubleshooting Test Steps Values Results
1. Check for Active Diagnostic Codes and Check for Logged Diagnostic Codes
A. Connect Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Download the "Product Status Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes.
C. Monitor the active diagnostic code screen on Cat ET. Record any active diagnostic codes.
Note. Wait at least 30 seconds in order for diagnostic codes to become active.
Logged Diagnostic Codes
Or
Active Diagnostic Codes
Results: A diagnostic code is logged but is not active.
Repair:Do not troubleshoot a logged code unless the code relates to an operator complaint. If the code is logged and the code does not relate to an operator complaint, clear the code.
If the logged code relates to this procedure, inspect the electrical connectors and the wiring for the circuit.
Refer to Troubleshooting, "Electrical Connectors - Inspect"
Results: A -3 code or -4 code is active for the 8 V digital supply.
Proceed to Test Step 2.
Results: A -3 code or -4 code is active for one of the 5 V analog supplies.
Proceed to