The Engine Control Module (ECM) monitors the fuel pressure for the Aftertreatment Regeneration Device (ARD). The ECM sets a diagnostic code if there is a problem with the fuel pressure for the ARD. Table 1 lists the diagnostic codes for the fuel pressure for the ARD.
| Diagnostic Trouble Codes for Problems With The Fuel Pressure for the ARD | ||
|---|---|---|
| J1939 Code | Description | Information |
| 3480-16 | Aftertreatment #1 Fuel Pressure #1 : High - Moderate Severity (2) | This code relates to main fuel pressure. The amber warning lamp is illuminated. One of the following conditions has occurred: The ARD is off. The purge air is off. The ECM is commanding the fuel enable valve to open. The ECM is commanding the main fuel control valve to close. The pressure in the main fuel line is greater than 200 kPa (29 psi) for at least 4 seconds. The ARD is on. The pressure in the main fuel line is 700 kPa (100 psi) greater than the desired pressure. The following conditions can cause this code: The main fuel control valve is stuck in the enabled position or the main fuel control valve is not operating correctly. The fuel enable valve is stuck open. This is the cause of the problem if the pilot fuel pressure is high and the main fuel pressure is high. The nozzle inside the ARD combustion head is plugged. |
| 4077-16 | Aftertreatment #1 Fuel Pressure #2 : High - Moderate Severity (2) | This code relates to pilot fuel pressure. The amber warning lamp is illuminated. The code is logged. One of the following conditions has occurred: The ARD is off. The purge air is off. The pressure in the pilot fuel line is greater than 200 kPa (29 psi) for at least 4 seconds. The ARD is on. The pressure in the pilot fuel line is 700 kPa (100 psi) greater than the desired pressure. The following conditions can cause this code: The pilot fuel control valve is stuck open or the pilot fuel control valve is not operating correctly. The fuel enable valve is stuck open. This is the cause of the problem if the pilot fuel pressure is high and the main fuel pressure is high. The nozzle inside the ARD combustion head is plugged. |
| 4077-17 | Aftertreatment #1 Fuel Pressure #2 : Low - Least Severe (1) | This code relates to pilot fuel pressure. The amber warning lamp is illuminated. The code is logged. Follow the troubleshooting procedure in order to identify the root cause of the problem. |
| 4077-18 | Aftertreatment #1 Fuel Pressure #2 : Low - Moderate Severity (2) | This code relates to pilot fuel pressure. The amber warning lamp is illuminated. Follow the troubleshooting procedure in order to identify the root cause of this code. |
| Follow the troubleshooting procedure in order to identify the root cause of the problem. | ||
Fuel System Schematic
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| Illustration 1 | g01443955 |
Fuel system schematic (1) Cylinder head (2) 550 kPa (80 psi) regulator (3) Fuel rail pressure sensor (4) Lines between the rail and the cylinder head (5) Rail (6) Pressure relief valve (7) 600 kPa (86 psi) regulator for the high-pressure fuel pump (8) High-pressure fuel pump (9) Fuel transfer pump (10) Fluid sampling valve (11) Secondary fuel filter (12) Backflow check valve (13) Optional hand priming pump (14) Fuel filter base (15) Forward fuel manifold (16) 1250 kPa (180 psi) pressure regulator (17) 500 kPa (72 psi) pressure regulator (18A) Fuel enable valve in the de-energized position (18B) Fuel enable valve in the energized position (19) Main fuel control valve (20) Pilot fuel control valve (21) Rear fuel manifold (22) Pilot fuel pressure sensor (23) Main fuel pressure sensor (24) Primary fuel filter (25) Fuel tank | |
Regulation of System Pressure
Fuel transfer pump (9) creates a fuel pressure of approximately 480 kPa (70 psi) when the ARD is off. This pressure is regulated by 500 kPa (72 psi) pressure regulator (17) . The ECM energizes fuel enable valve (18) during an active regeneration. The energized valve moves to position (18B) . This places 1250 kPa (180 psi) pressure regulator (16) into the circuit. The pressure at the outlet of the fuel transfer pump rises to approximately 1725 kPa (250 psi). Fuel at this pressure is available for the ARD.
Component Identification
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| Illustration 2 | g01387704 |
Left side of the engine Regulator (7) is behind pump (8) . (1) Cylinder head (2) 550 kPa (80 psi) regulator (3) Fuel rail pressure sensor (4) Lines between the rail and the cylinder head (5) Rail (6) Pressure relief valve (8) High-pressure fuel pump (9) Fuel transfer pump (10) Fluid sampling valve (11) Secondary fuel filter (12) Backflow check valve (13) Optional hand priming pump (14) Fuel filter base (15) Forward fuel manifold (16) 1250 kPa (180 psi) pressure regulator (17) 500 kPa (72 psi) pressure regulator (18) Fuel enable valve (19) Pilot fuel control valve (20) Main fuel control valve (21) Rear fuel manifold (22) Pilot fuel pressure sensor (23) Main fuel pressure sensor | |
Lines and Ports
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| Illustration 3 | g01444224 |
Configuration for C7 engines and C9 engines that are not installed in recreational vehicles (26) Line from the outlet of the fuel filter base to the inlet of the high-pressure fuel pump (27) Inlet to the high-pressure fuel pump (28) Line from the outlet of the high-pressure fuel pump to the rail (29) Port for pressurized oil for the high-pressure fuel pump (30) Line from the forward manifold to the inlet of the fuel transfer pump (31) This support provides a passage for return fuel from regulator (7) to vehicle fuel tank. (32) Line for return fuel from regulator (7) to the vehicle fuel tank (33) Line for return fuel from the cylinder head (34) Line for return fuel from the rail (35) Port for purge air to the ARD (36) Ports for return fuel to the vehicle fuel tank (37) Line from the forward fuel manifold to the inlet of the fuel filter base (38) Fuel line from the primary fuel filter (39) Line from the outlet of the fuel transfer pump to the forward fuel manifold (40) Line for main fuel to the rear fuel manifold (41) Line for pilot fuel to the rear fuel manifold | |
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| Illustration 4 | g01444231 |
Configuration for C9 engines that are installed in recreational vehicles (27) Inlet to the high-pressure fuel pump (28) Line from the outlet of the high-pressure fuel pump to the rail (29) Port for pressurized oil for the high-pressure fuel pump (30) Line from the forward manifold to the inlet of the fuel transfer pump (32) Line for return fuel from regulator (7) to the vehicle fuel tank (33) Line for return fuel from the cylinder head (34) Line for return fuel from the rail (35) Port for purge air to the ARD (36) Ports for return fuel to the vehicle fuel tank (37) Line from the forward fuel manifold to the inlet of the fuel filter base (39) Line from the outlet of the fuel transfer pump to the forward fuel manifold (40) Line for main fuel to the rear fuel manifold (41) Line for pilot fuel to the rear fuel manifold (42) Line for fuel from the fuel transfer pump via the rear fuel manifold (43) Port for fuel from the primary fuel filter | |
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| Illustration 5 | g01444290 |
Electrical schematic for the valves in the ARD fuel system Pilot fuel control valve (19) is behind the air inlet heater relay. (18) Fuel enable valve (19) Main fuel control valve (20) Pilot fuel control valve (44) ECM | |
Control of Pilot Fuel Pressure and Main Fuel Pressure
Refer to Illustration 5. There is one electrical circuit for both of the fuel control valves. The valves are connected in series. The ECM creates one PWM command in order to control both of the valves. The maximum current flow through the circuit is approximately 2.5 A.
Each control valve contains a spring. The spring in the pilot fuel control valve is weaker than the spring in the main fuel control valve. Refer to Illustration 6. The lower spring pressure in the pilot fuel control valve causes the pilot fuel control valve to open when the flow of current is low. A current flow of approximately 1.2 A is required in order to open the pilot fuel control valve. However, the higher spring pressure in the main fuel control valve caused the main fuel control valve to remain closed at 1.2 A. A current flow of approximately 1.3 A is required in order for the main fuel control valve to start to open. A current flow of approximately 2.5 A is required in order to open the main fuel control valve.
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| Illustration 6 | g01384347 |
Current flow versus total fuel flow for the ARD | |
An electrical problem with the circuit affects both of the control valves. Therefore, both of the control valves are disabled if there is a short circuit or an open circuit.
Test Step 1. Determine the Diagnostic Code
Establish communication between Cat ET and the engine ECM. Look for the following codes:
- 3480-16
- 3480-18
- 4077-16
- 4077-17
- 4077-18
Expected Result:
One of the above codes is present.
Results:
- A 3480-16 code and a 4077-16 code are both present. - The fuel enable valve is stuck open. This causes both fuel pressures to be high.
Repair: Replace fuel enable valve (18) .
Proceed to Test Step 4.
- Only a 3480-16 code or a 3480-18 code is present. - The main fuel control valve is not working correctly.
Repair: Replace main fuel control valve (20) .
Proceed to Test Step 4.
- Only a 4077-16 code is present. - The pilot fuel control valve is not working correctly.
Repair: Replace pilot fuel control valve (19) .
Proceed to Test Step 4.
- A 4077-17 code or a 4077-18 code is present. The fuel system pressure is low. - Proceed to Test Step 2.
Test Step 2. Check the Pressure at the Outlet of the Fuel Transfer Pump
This test step checks the pressure at the outlet of the fuel transfer pump when the ARD is off.
- Insert a tee in line (39) between the outlet of the fuel transfer pump and the forward fuel manifold. Connect a pressure gauge to the tee.
- Disable the ARD by setting the value of the "Data Link Disable ARD Status" parameter to "Disabled". The parameter is in "Emissions Parameters".
- Start the engine. Observe the fuel pressure on the gauge. Stop the engine.
Expected Result:
The outlet pressure for the fuel transfer pump is above 450 kPa (65 psi).
Results:
- The outlet pressure of the fuel transfer pump is above 450 kPa (65 psi). - The outlet pressure of the fuel transfer pump is OK. Proceed to Test Step 3.
- The outlet pressure of the fuel transfer pump is below 450 kPa (65 psi). - The fuel transfer pump has low outlet pressure.
Repair: The following procedure determines the cause of low pressure at the outlet of the fuel transfer pump. Accomplish the procedure by using the following technique:
- Repair the component or replace the component if the component is faulty.
- Start the engine. Check the pressure again.
- Continue to the next component if the pressure is still below 450 kPa (65 psi).
- Replace the primary fuel filter.
- Replace 500 kPa (72 psi) pressure regulator (17) .
- Replace 600 kPa (86 psi) regulator (7) .
Show/hide table
Illustration 7 g01388721
Top view of the front left corner of the engine
(5) Rail
(7) 600 kPa (86 psi) regulator for the high-pressure fuel pump
(8) High-pressure fuel pump
- Replace fuel transfer pump (9) .
Proceed to Test Step 3 after the pressure at the outlet of the fuel transfer pump is at least 450 kPa (65 psi).
- Repair the component or replace the component if the component is faulty.
Test Step 3. Check the Pressure at the Outlet of the Fuel Transfer Pump During an Active Regeneration
The pressure at the outlet of the fuel transfer pump must be at least 450 kPa (65 psi) in order to perform this test step.
- Enable the ARD by setting the value of the "Data Link Disable ARD Status" parameter to "Not Disabled". The parameter is in "Emissions Parameters".
- Start the engine.
- Start an active regeneration by setting the value of the "ARD Override" to "Active".
- Wait for 60 seconds. Observe the fuel pressure on the gauge.
- Disable the active regeneration by setting the value of the "ARD Override" to "Not Active".
Expected Result:
The outlet pressure of the fuel transfer pump was above 1375 kPa (200 psi).
Results:
- The outlet pressure of the fuel transfer pump was above 1375 kPa (200 psi). - The pressure is OK. The low pilot fuel pressure was caused by the pilot fuel control valve.
Repair: Replace pilot fuel control valve (20) .
Proceed to Test Step 4.
- The outlet pressure of the fuel transfer pump was less than 1375 kPa (200 psi). The pressure is low when the ARD is on. -
Repair: Perform the following procedure. Accomplish the procedure by using the following technique:
- Repair the component or replace the component if the component is faulty.
- Activate the ARD after the component is replaced. Check the fuel pressure during the active regeneration. Disable the regeneration after you check the pressure.
- Continue to the next component if the fuel pressure is still below 1375 kPa (200 psi).
- Replace 1250 kPa (180 psi) pressure regulator (16) .
- Replace fuel enable valve (18) .
- Start an active regeneration by setting the value of the "ARD Override" to "Active".
- Monitor the value of the "ARD Pilot Fuel Pressure" during the regeneration. The parameter is in the "Aftertreatment Regeneration 3" status group. The "ARD Pilot Fuel Pressure" should be equal to the pressure on the gauge after 5 minutes of operation of the ARD.
Replace pilot fuel control valve (20) if the pressures are not equal after 5 minutes of operation of the ARD.
Disable the regeneration and proceed to test step 4 if the pressures are equal after 5 minutes of operation of the ARD.
- Repair the component or replace the component if the component is faulty.
Test Step 4. Perform a Stationary Regeneration
- Click the "Disconnect" icon on Cat ET in order to disconnect Cat ET from the engine.
| NOTICE |
|---|
A 3715-31 code indicates that the DPF contains too much soot. Replace the DPF before clearing this code. If a 3715-31 code is cleared and the Diesel Particulate Filter (DPF) is not replaced, an active regeneration will destroy the DPF. |
- Turn the keyswitch to the OFF position. Wait for 5 seconds.
- Turn the keyswitch to the ON position.
- Click the "Connect" icon on Cat ET in order to connect Cat ET to the engine.
- Start the engine. Allow the engine to idle for 3 minutes.
- Start a stationary regeneration by selecting the following menus on Cat ET:
- "Service"
- "Service Procedures"
- "Manual Diesel Particulate Filter Regeneration"
Cat ET will display a "Waiting On Requirements" window. The ECM will automatically elevate the engine speed to 1400 rpm. If the "Waiting On Requirements" window remains displayed for more than 5 minutes, abort the regeneration. Then, select the menu options again in order to start the stationary regeneration.
The duration of the stationary regeneration depends on the soot load in the DPF. The ECM will automatically return the engine speed to low idle after the stationary regeneration is complete.
Note: The ECM tests the nozzles for plugging after the stationary regeneration is complete. Approximately 10 minutes are required in order for the test to provide a result. A code will become active if the nozzles are plugged.
- "Service"
Results:
- The stationary regeneration completed successfully. - STOP
- The stationary regeneration did not complete successfully. -
Repair: Refer to Troubleshooting, "ARD Stationary Regeneration Does Not Activate".
STOP