EDGE AS 4763431 - Caterpillar

Table 1
Diagnostic Trouble Codes for Sensor Supplies
J1939 Code CDL Code Code Description
(code descriptions may vary) Comments
678-3 41-3 ECU 8 Volts DC Supply : Voltage Above Normal The ECM detects the following conditions:
The 8 VDC supply is more than 8.8 VDC for more than one second.
The ECM has been powered for more than 3 seconds.
Diagnostic code 168-4 is not active.
The ECM will log the diagnostic code and the warning lamp will illuminate when this diagnostic code is active.
The engine may be limited to low idle.
678-4 41-4 ECU 8 Volts DC Supply : Voltage Below Normal The ECM detects the following conditions:
The 8 VDC supply is less than 7.2 VDC for more than one second.
The ECM has been powered for more than 3 seconds.
Diagnostic code 168-4 is not active.
The ECM will log the diagnostic code and the warning lamp will illuminate when this diagnostic code is active.
The engine may be limited to low idle.
An active diagnostic code may not cause any noticeable effect on engine response unless the voltage drops below 6.5 VDC.
3509-3 262-3 Sensor Supply Voltage 1 : Voltage Above Normal The Electronic Control Module (ECM) detects the following conditions:
The 5 VDC supply for the sensors is greater than 5.16 VDC for more than one second.
The ECM has been powered for at least 3 seconds.
Diagnostic code 168-4 is not active.
The warning lamp will come on. The ECM sets all the sensors on the 5 VDC circuit to the default values.
The engine will be derated.
3510-3 2131-3 Sensor Supply Voltage 2 : Voltage Above Normal
3509-4 262-4 Sensor Supply Voltage 1 : Voltage Below Normal The ECM detects the following conditions:
The 5 VDC supply for the sensors is less than 4.84 VDC for more than one second.
The ECM has been powered for at least 3 seconds.
Diagnostic code 168-4 is not active.
The warning lamp will come on. The ECM sets all the sensors on the 5 VDC circuit to the default values.
The engine will be derated.
3510-4 2131-4 Sensor Supply Voltage 2 : Voltage Below Normal Note: A 678-XX diagnostic code indicates a fault in the 8 VDC circuit on the J1/P1 connector. A 3509-XX diagnostic code indicates a fault in the 5 VDC circuit on the J2/P2 connector. A 3510-XX diagnostic code indicates a fault in the 5 VDC circuit on the J1/P1 connector.The following background information is related to this procedure:The ECM supplies regulated +5 VDC to the following sensors on P2:1:
Barometric pressure sensor
Intake manifold air pressure sensor
Fuel pressure sensor
Engine oil pressure sensor
NRS intake pressure sensor
NRS differential pressure sensor
NRS valve position sensor
Exhaust Back Pressure Regulator (EBPR) position sensorA diagnostic code can be caused by the following conditions:
A short circuit in the harness
A faulty sensor
An open circuit in the harness
Illustration 1 g03713485
Typical example of the schematic for the 5 VDC supply on P2:1
Note: Refer to the Electrical Schematic for the application for information regarding components that are connected to the 5 V and 8 V supplies on the J1/P1 connector.
Illustration 2 g02315513
Typical example of the fuel rail pressure sensor
(1) Sensor ground
(3) 5 VDC supplyNote: The