C2.2 Engines For Caterpillar Built Machines Caterpillar

Sensor Supply - Test

Usage:

239D BL9

This procedure covers the following diagnostic codes:

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Table 1
Diagnostic Trouble Codes for Sensor Supplies
J1939 Code	Code Description	Comments
3509-3	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 5.63 VDC for more than one second. The ECM has been powered for at least 2 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	Sensor Supply Voltage 2 : Voltage Above Normal
3509-4	Sensor Supply Voltage 1 : Voltage Below Normal	The ECM detects the following conditions: The 5 VDC supply for the sensors is less than 4.38 VDC for more than one second. The ECM has been powered for at least 2 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	Sensor Supply Voltage 2 : Voltage Below Normal

The following background information is related to this procedure:

The ECM supplies regulated +5 VDC to the following sensors:

Intake manifold air pressure sensor
Fuel rail pressure sensor
Intake throttle valve position sensor (if equipped)
NRS valve position sensor
Camshaft speed/timing sensor

A diagnostic code can be caused by the following conditions:

A short circuit in the harness
A faulty sensor
An open circuit in the harness

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Illustration 1	g06097792
Schematic for the 5 VDC supply 1

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Illustration 2	g06088268
Schematic for the 5 VDC supply 2

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Illustration 3	g03834424
Fuel rail pressure sensor (1) 5 VDC Supply (3) Ground

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Illustration 4	g03834769
Typical example of an engine pressure sensor (2) Ground (3) 5 VDC Supply

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Illustration 5	g03826056
Connector for the NRS valve (2) +5 VDC (3) Ground

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Illustration 6	g03826026
Connector for the intake throttle valve (if equipped) (3) Ground (5) +5 VDC

Complete the procedure in the order in which the steps are listed.

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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 while 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 logged when a sensor is unplugged. Repair: Replace the failed sensor. Verify that the repair resolved the fault. Result: The suspect sensor supply active code remains active after all sensors on the sensor supply circuit have been checked. Proceed to Test Step 3.
3. Check the Wiring for an Open Circuit A. Turn the keyswitch to the OFF position. B. Disconnect all sensors on the suspect 5 VDC supply circuit. C. Disconnect the engine interface connector. D. Disconnect the J1 and J2 connector from the ECM, as applicable. 5 VDC Supply Circuit 1 E. Measure the following resistances: · Pin 1 on the fuel rail pressure sensor harness connector to pin 27 on the sensor side of the engine interface connector. · Pin 3 on the fuel rail pressure sensor harness connector to pin 8 on the sensor side of the engine interface connector. · Pin 27 on the ECM side of the engine interface connector to P2:45. · Pin 8 on the ECM side of the engine interface connector to P2:16. 5 VDC Supply Circuit 2 F. Measure the following resistances: · Pin 3 on the intake throttle valve harness connector to pin 5 on the sensor side of the engine interface connector. · Pin 5 on the intake throttle valve harness connector to pin 14 on the sensor side of the engine interface connector. · Pin 5 on the ECM side of the engine interface connector to P2:12. · Pin 14 on the ECM side of the engine interface connector to P2:24. · Pin 2 on the NRS valve harness connector to pin 12 on the sensor side of the engine interface connector. · Pin 3 on the NRS valve harness connector to pin 5 on the sensor side of the engine interface connector. · Pin 12 on the ECM side of the engine interface connector to P2:22. · Pin 2 on the intake manifold air pressure sensor harness connector to pin 6 on the sensor side of the engine interface connector. · Pin 3 on the intake manifold air pressure sensor harness connector to pin 13 on the sensor side of the engine interface connector. · Pin 6 on the ECM side of the engine interface connector to P2:14. · Pin 13 on the ECM side of the engine interface connector to P2:23. · Pin 2 on the camshaft speed/timing sensor harness connector to pin 10 on the sensor side of the engine interface connector. · Pin 3 on the camshaft speed/timing sensor harness connector to pin 45 on the sensor side of the engine interface connector. · Pin 10 on the ECM side of the engine interface connector to P2:18. · Pin 45 on the ECM side of the engine interface connector to P1:9. G. Reconnect the J1 and J2 connector to the ECM, as applicable. H. Reconnect the engine interface connector. I. Reconnect all sensors on the suspect 5 VDC supply circuit.	Less than 2.0 Ohms	Result: A measured resistance is more than 2.0 Ohms. Repair: Repair or replace the wiring harness. Result: All measured resistances are less than 2.0 Ohms. Proceed to Test Step 4.
4. Check the Wiring for a Short Circuit A. Turn the keyswitch to the OFF position. B. Disconnect all sensors on the suspect 5 VDC supply circuit. C. Disconnect the engine interface connector. D. Disconnect the J1 and J2 connector from the ECM, as applicable. 5 VDC Supply Circuit 1 E. Measure the following resistances: · Pin 27 on the sensor side of the engine interface connector to all other pins on the connector. · Pin 8 on the sensor side of the engine interface connector to all other pins on the connector. · P2:45 to all other pins on the P2 connector. · P2:16 to all other pins on the P2 connector. 5 VDC Supply Circuit 2 F. Measure the following resistances: · Pin 5 on the sensor side of the engine interface connector to all other pins on the connector. · Pin 14 on the sensor side of the engine interface connector to all other pins on the connector. · P2:12 to all other pins on the P2 connector. · P2:24 to all other pins on the P2 connector. · Pin 12 on the sensor side of the engine interface connector to all other pins on the connector. · P2:22 to all other pins on the P2 connector. · Pin 6 on the sensor side of the engine interface connector to all other pins on the connector. · Pin 13 on the sensor side of the engine interface connector to all other pins on the connector. · P2:14 to all other pins on the P2 connector. · P2:23 to all other pins on the P2 connector. · Pin 10 on the sensor side of the engine interface connector to all other pins on the connector. · Pin 45 on the sensor side of the engine interface connector to all other pins on the connector. · P2:18 to all other pins on the P2 connector. · P1:9 to all other pins on the P1 connector. G. Reconnect the J1 and J2 connector to the ECM, as applicable. H. Reconnect the engine interface connector. I. Reconnect all sensors on the suspect 5 VDC supply circuit.	At least 1k Ohm	Result: A measured resistance is less than 1k Ohm. Repair: Repair or replace the wiring harness. Result: All measured resistances are more than 1k Ohm. Contact the Dealer Solutions Network (DSN).