ORIFICE 1246657 - Caterpillar

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. The 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 in order to determine if a sensor has failed.
Illustration 1 g03844609
Illustration 2 g01240891
Sensor connector
(Terminal 1) Sensor supply
(Terminal 2) Sensor return
(Terminal 3) Signal
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Determine if a code is active or logged.
Codes
Result: A -3 or -4 code is active. Note which ECM is reporting the active code.
Proceed to Test Step 2.
Result: A -21 code is active.
Proceed to Test Step 3.
2. Check for a Failed Sensor
A. Connect Cat ET.
B. Disconnect a sensor on the affected sensor supply circuit.
C. Use Cat ET to monitor following:
- Active code changes to logged
D. Connect the affected sensor to the wiring harness.
E. Repeat Step B through Step D for each sensor on the affected sensor supply.
Sensor
Result: The affected sensor supply active code changed to a logged code when a sensor is unplugged.
Repair: Repair or replace the failed sensor.
Verify that the repair eliminated the problem.
Result: The affected sensor supply active code remains active after all the sensors on the sensor supply circuit have been checked.
Repair: A failed wiring harness has been detected. Repair or replace the wiring harness.
Verify that the repair eliminated the problem.
3. Check the Sensor Supply
A. Turn the keyswitch to the OFF position.
B. Unplug the sensor from the wiring harness.
C. Install the jumper wire between the following terminals at the sensor connector:
- Terminal 1 (sensor supply) and Terminal 2 (sensor return)
D. Connect Cat ET.
E. Use Cat ET to monitor the following:
- Codes
Codes
Result: A -4 code