SEAL-O-RING 2256948 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with the fuel pump relay. Or, use this procedure if one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table
J1939 Code and Description Conditions which Generate this Code System Response
931-5 Engine Fuel Supply Pump Actuator : Current Below Normal The engine Electronic Control Module (ECM) detects an open circuit at the fuel pump relay for 60 seconds.
The ECM detects a short to battery voltage for the fuel pump relay.
The ECM can only detect this condition when the output driver is not activated. The code is logged.
931-6 Engine Fuel Supply Pump Actuator : Current Above Normal The engine ECM detects a short circuit for the fuel pump relay.
The ECM can only detect this condition when the output driver is activated. The ECM can energize the fuel pump relay. The fuel pump relay controls battery power to the fuel priming pump.ECM Activation of the Fuel Priming PumpThis strategy improves the capability of the fuel system at low engine speeds.The ECM will automatically activate the fuel priming pump while the engine state is CRANKING, RUNNING, or POSTRUN. The ECM deactivates the fuel pump when the engine speed is greater than 200 rpm. Manual Override of the Fuel Priming PumpA "Fuel Priming Pump Command Override" that is in Caterpillar Electronic Technician (ET) can be used to diagnose the pump circuit. A "Fuel Priming Pump Command" parameter is also available in Cat ET that can be used to view the status of the ECM output.When the override is activated, the ECM powers the electric fuel priming pump. The ECM will command the throttle position to 25 percent. A path is then provided for air to escape from the low-pressure fuel system. To use this feature, the ECM and the keyswitch relay must be powered. Also, the engine speed must be 0 rpm.
Illustration 1 g02700809
Schematic for the electric fuel priming pump
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the main disconnect switch to the OFF position.
Illustration 2 g02721290
Location of the J1/P1 and the J2/P2 ECM connectors (typical engine view)
(1) J1/P1 ECM connector
(2) J2/P2 ECM connector
Thoroughly inspect connector (1). Also, thoroughly inspect the power interface connector and any other connectors associated with the circuit. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01447112
Terminal locations for the high-pressure fuel pump at the P1 ECM connectors
(P1-10) Fuel priming pump
Illustration 4 g02702261
Terminal locations at the right rail connector for the electric fuel priming pump
(Terminal 32) Return
(Terminal 31) + Battery
Illustration 5 g01535553
Terminal locations at the power interface connector that are for the electric fuel priming pump
(60) Return
(59) + Battery
(24) Signal voltage to relay
Illustration 6 g01155187
Terminal locations at the connector for the electric fuel priming pump
(Terminal 1) Relay signal circuit to the pump
(Terminal 2) Return
Check the torque of the allen head screws for each of the ECM connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion