PISTON ASSEM. 2P3752 - Caterpillar

This procedure covers the following diagnostic codes:
Table 1
Diagnostic Codes for the Active Analog Sensors
J1939 Code Code Description Comments
102-3 Engine Intake Manifold #1 Pressure : Voltage Above Normal The Electronic Control Module (ECM) detects a signal voltage that is not in the acceptable range.
The code is logged.
The value of the parameter is set to a gauge pressure.
102-4 Engine Intake Manifold #1 Pressure : Voltage Below Normal The ECM detects a signal voltage that is not in the acceptable range.
The code is logged.
The value of the parameter is set to a gauge pressure.
108-3 Barometric Pressure Sensor : Voltage Above Normal The ECM detects signal voltage that is not in the acceptable range.
The code is logged.
This sensor is integrated into the engine ECM. Contact the Dealer Solutions Network (DSN) for advice.
108-4 Barometric Pressure Sensor : Voltage Below Normal The ECM detects signal voltage that is not in the acceptable range.
The code is logged.
This sensor is integrated into the engine ECM. Contact the Dealer Solutions Network (DSN) for advice.
157-3 Engine Injector Metering Rail #1 Pressure : Voltage Above Normal The ECM detects signal voltage that is not in the acceptable range.
The code is logged.
The value of the parameter is set to a gauge pressure.
157-4 Engine Injector Metering Rail #1 Pressure : Voltage Below Normal The ECM detects signal voltage that is not in the acceptable range.
The code is logged.
The value of the parameter is set to a gauge pressure.
Follow the troubleshooting procedure to identify the root cause of the fault. The following conditions must exist before any of the above codes will become active:
There are no active 3509 codes.
There are no active 168 codes.The following background information is related to this procedure:The 5 VDC sensor supply provides power to all 5 VDC sensors. The ECM supplies 5 VDC to terminal "1" of the fuel rail pressure sensor connector and to terminal "3" of the inlet manifold pressure sensor. The sensor common from the ECM connector goes to terminal "3" of the connector for the fuel rail pressure sensor. The sensor common from the ECM connector goes to terminal "2" of the inlet manifold pressure sensor.
Illustration 1 g06030260
Schematic for the active sensors
Illustration 2 g03834424
Fuel rail pressure sensor
(1) 5 VDC Supply
(2) Signal
(3) Ground
Illustration 3 g03834769
Intake manifold pressure sensor
(1) Signal
(2) Ground
(3) 5 VDC Supply
Table 2
Troubleshooting Test Steps Values Results
1. Check for Diagnostic Codes
A. Establish communication between the electronic service tool and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Turn the keyswitch to the ON position.
C. Look for a -3, or -4 active or logged code:
Diagnostic code
Result: A 157-X diagnostic code is active.
Proceed to Test Step 2.
Result: A 102-X diagnostic code is active.
Proceed to Test Step 4.
Result: A 108-X diagnostic code is active.
Contact the Dealer Solutions Network (DSN).
2. Check the Wiring between the Fuel Rail Pressure Sensor and the ECM for an Open Circuit
Refer to Illustration 1.
A. Turn the keyswitch to the OFF position.
B. Disconnect the harness connector from the fuel rail pressure sensor.
C. Disconnect the engine interface connector.
D. Disconnect the J2 connector from the