Series 50G/60G Troubleshooting – Section 5.11 PID 94, FMI 1, Flash Code 48, Fuel Pressure Low

Section 5.11
PID 94, FMI 1, Flash Code 48, Fuel Pressure Low

The fuel pressure is low due to a faulty sensor connection, a faulty sensor, problem in the fuel system, a short or an open wire.‪

Section 5.11.1
Troubleshooting

Troubleshoot as follows:‪

1. Check wire 905 (yellow, Fuel Pressure Sensor) cavity M-1 in the Engine Sensor Harness (ESH) 30–pin connector (see Figure "Engine Sensor Harness 30–pin Connector" ). If there is a short or an open wire, repair or replace the wire(s), pins, and sockets.
   

   Figure 1. Engine Sensor Harness 30–pin Connector

   1. If the code is still active, go to step .
   2. If the code is no longer active, refer to "5.11.2 Verification" .
2. Check the Fuel Pressure Sensor (FPS) using the DDEC Sensor Tester J 37164 (see Figure "DDEC Sensor Tester J 37164" ).
   

   Figure 2. DDEC Sensor Tester J 37164

3. Disconnect the sensor. On Series 60G and 50G engines with a high pressure fuel system, the FPS is installed in a tee at the inlet to the low pressure regulator (see Figure "Fuel Pressure Sensor Location" ).
   

   Figure 3. Fuel Pressure Sensor Location

4. Disengage the locking tang on the three-wire connector. Grasp the body of the connector and gently pull it free of the FPS.
5. Use the appropriate wrench on the hex end of the FPS to unscrew it from the inlet tee.
6. Connect the sensor to the tester at the correct connector.
7. Clip the power leads to the 12 volt power source.
8. Plug in a volt OHM meter. The tester will power up the sensor.
   1. If the FPS needs to be replaced, refer to "5.11.1.1 Replacing the Fuel Pressure Sensor" .
   2. If the FPS does not need to be replaced, go to Step .
9. Check the fuel system and fuel tanks and repair if necessary.
   1. If the code is still active, go to step .
   2. If the code is no longer active, refer to "5.11.2 Verification"
10. Check wire 909 (light green, PWM No. 2 out) cavity Y-1 to see if there is a short to wire 416 (gray, sensor supply, 5VDC) cavity W-1 in the ESH 30–pin connector (see Figure "Engine Sensor Harness 30–pin connector" ). If there is a short, repair or replace the wire(s), pins, and sockets.
    

    Figure 4. Engine Sensor Harness 30–pin connector

    1. If the code is still active, go to step .
    2. If the code is no longer active, refer to "5.11.2 Verification" .
11. Check pin E (PWM No. 2 out) in the PSV connector (see Figure "PSV Connector" ). If there is a short, repair or replace the wire(s), pins, and sockets.
    

    Figure 5. PSV Connector

    1. If the code is still active, go to step .
    2. If the code is no longer active, refer to "5.11.2 Verification" .
12. Check wire 452 (black, engine sensor return) cavity Y-2 in the ESH 30–pin connector to see if it is open (see Figure "Engine Sensor Harness 30–pin connector" ). Also check pin D (engine sensor return) in the throttle actuator connector (see Figure "Throttle Actuator Connector" ). Repair or replace any open wires, pins, and sockets.
    

    Figure 6. Throttle Actuator Connector

    1. If the code is still active, call Detroit Diesel Technical Service.
    2. If the code is no longer active, refer to "5.11.2 Verification"

Section 5.11.1.1
Replacing the Fuel Pressure Sensor

The FPS is non-servicable and should be replaced as a unit. No adjustment is required.‪

Replace the FPS as follows:‪

Note: The FPS is an electrical device. Use care on installation.

1. On the replacement FPS, use Loctite® Pipe Sealant with Teflon, PT-7260, or equivalent on all but the first two threads of the FPS to prevent leaks.
2. Screw FPS into the regulator inlet tee.
3. Engage locking tang of the three wire connector to the FPS.
4. Turn the ignition to the ON position. Observe the DDR for any diagnostic code(s).
   1. If PID 94, FMI 1, Flash Code 48 is still active, call Detroit Diesel Technical Service.
   2. If PID 94, FMI 1, Flash Code 48 is not active. Refer to "5.11.2 Verification" .

Section 5.11.2
Verification

Verify troubleshooting as follows: ‪

1. Check the DDR to see if PID 94, FMI 1, Flash Code 48 is still active.
   1. If the code is still active, go to step 2.
   2. If the code is not active, troubleshooting is complete.
2. If the code is still active, call Detroit Diesel Technical Service.