SPRING 2933608 - Caterpillar

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 +8 VDC to the following sensors on the P1 connector:
Digital throttle position sensor 1
Digital throttle position sensor 2The ECM supplies regulated +8 VDC to the following sensors on the P2 connector:
Primary speed/timing sensor
Secondary speed/timing sensorThe ECM supplies regulated +5 VDC to the following sensors on the P1 connector:
Analog throttle position sensor 1
Analog throttle position sensor 2
DPF inlet temperature sensor
Aftertreatment identification moduleThe ECM supplies regulated +5 VDC to the following sensors on the P2 connector:
Barometric pressure sensor
Intake manifold air pressure sensor
Fuel pressure sensor
Engine oil pressure sensor
NRS intake pressure sensor
NRS outlet 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 g06104117
Typical example of the schematic for the 8VDC supply on P1 and P2
Illustration 2 g06104168
Typical example of the schematic for the 5 VDC supply on P1
Illustration 3 g06114261
Typical example of the schematic for the 5 VDC supply on P2
Note: Refer to the application electrical schematic for components that are connected to the 5 V and 8 V supplies on the P1 and P2 connectors.
Illustration 4 g02315513
Typical example of the fuel rail pressure sensor
(1) Sensor ground
(3) 5 VDC supplyNote: The position of the terminal for the voltage supply on the fuel rail pressure sensor is different to all other engine pressure sensors.
Illustration 5 g02315514
Typical example of an engine pressure sensor
(1) 5 VDC supply
(2) Sensor ground
Illustration 6 g02315534
Typical example of the connector for the NRS valve
(1) 5 VDC supply
(2) Sensor ground
Illustration 7 g03130436
Typical example of the connector for the Exhaust Back Pressure Regulator (EBPR)
(1) 5 VDC supply
(2) Ground
Illustration 8 g02087493
Typical example of the connector for the DPF inlet temperature sensor
(1) 5 VDC supply
(2) Ground
Illustration 9 g02084579
Typical example of the connector for the aftertreatment identification module
(1) 5 VDC supply
(6) GroundComplete the procedure in the order in which the steps are listed.
Table 2
Troubleshooting Test Steps Values Results
1. Determine the Code
A. Connect the electronic service tool to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Turn the keyswitch to the ON position.
C. Determine if a diagnostic trouble code is present.
Diagnostic Codes
Result: A -3 or -4 code is present.
Note which sensor supply has the active diagnostic code.
Proceed to Test Step 2.
2. Check for a Failed Sensor
A. Connect to the electronic service tool.
B. Turn the keyswitch to the ON position.
C. Disconnect a sensor on the suspect sensor supply circuit.
D. Monitor the electronic service tool when the sensor is disconnected to see if the active code changes to logged.
E. Connect the suspect sensor to the wiring harness
F. Repeat steps C through E for each sensor on the suspect sensor supply.
Failed Sensor
Result: The suspect sensor supply active code changes to