Fuel Tank And Lines - V6 S/C 3.0L Petrol (G2278767): Operation: Notes
There is no separate fuel line to return fuel the tank. The system allows the LP fuel pump to deliver fuel to the HP fuel pumps, dependent on engine demand. The Low Pressure (LP) fuel pump operation is regulated by the Fuel Pump Driver Module (FPDM), which is controlled by the Powertrain Control Module (PCM). The FPDM controls the operation of the LP fuel pump to regulate the fuel flow and pressure delivered to the High Pressure (HP) fuel pumps. The PCM uses a Pulse Width Modulation (PWM) signal to control the LP fuel pump output fuel flow and pressure.
The PCM uses the low fuel pressure sensor to make sure that the required fuel pressure is delivered by the LP fuel pump to the HP fuel pumps.
The FPDM is supplied power via a fuel pump relay in the Rear Junction Box (RJB). The fuel pump relay is controlled by the Body Control Module/Gateway Module (BCM/GWM) and is active when the ignition is in all Power Modes except for Power Mode 0 (OFF). The PCM is connected to the BCM/GWM to receive a 'wake-up' message.
The fuel pump relay is energized:
- The drivers door is opened.
- The ignition switch only is pressed.
- The footbrake pedal is pressed and the ignition switch is also pressed (which initiates engine cranking).
The FPDM supplies power to the LP fuel pump, and adjusts the power to control the speed of the LP fuel pump. This control the pressure and flow in the fuel line from the LP fuel pump.
The PCM sends a PWM signal to the FPDM to control the speed for the LP fuel pump. The duty cycle of the PWM signal represents half the LP fuel pump speed. For example, if the PWM signal has a duty cycle of 50%, the FPDM drives the pump at 100%.
The FPDM will only energize the LP fuel pump if it receives a valid PWM signal, with an on duty cycle of between 4% and 50%. To switch the LP fuel pump OFF, the PCM transmits a PWM signal with a duty cycle of 75%.
The output pressure from the LP fuel pump will change with changes of engine demand and fuel temperature. The PCM monitors the input from the low fuel pressure sensor and adjusts the speed of the LP fuel pump as necessary to maintain a target output pressure.
| Engine condition | Target Output Pressure |
|---|---|
| Normal engine running (Power Mode 7) | 4.5 bar (65.3 psi) |
| Engine cranking (Power Mode 9) | 6.3 bar (91.4 psi) |
In the event of an impact the Restraints Control Module (RCM) outputs a crash signal to the BCM/GWM to disable the LP fuel pump relay. The BCM/GWM de-energizes the fuel pump relay to prevent any further fuel being pumped to the engine.
If the PCM does not detect pressure in the fuel delivery line, it stops the engine and stores the appropriate Diagnostic Trouble Code (DTC). The PCM also stops any engine restarts.
The PCM receives a monitoring signal from the FPDM. Any DTCs produced by the FPDM are stored by the PCM.
DTCs can be retrieved from the PCM using the Jaguar Land Rover (JLR) approved diagnostic equipment. The FPDM itself cannot be interrogated by the JLR approved diagnostic equipment.
For additional information, refer to: ELECTRONIC ENGINE CONTROLS
Fuel Level Sensor
Inside the fuel tank are 2 fuel level sensors A and B, which output signals to the Body Control Module/Gateway Module (BCM/GWM) for fuel tank fuel level.
The electrical output signal of the fuel level sensors is dependent on:
- The amount of fuel in each side of the fuel tank.
- The position of the float arms.
The fuel level sensors measure the resistance and is transmit the data to the BCM/GWM which implements an anti-slosh function. The anti-slosh function monitors the signals and updates the fuel level signal to the instrument cluster at regular intervals. The anti-slosh prevents constant fuel gauge pointer movement caused by fuel movement in the fuel tank due to cornering or braking. The low level fuel warning indicator in the Instrument Cluster (IC) illuminates when the fuel level in the tank falls below a predetermined level.
The fuel level sensor signals are converted in the BCM/GWM into High Speed (HS) Controller Area Network (CAN) comfort systems bus messages. The fuel level messages are used by the:
- IC for fuel gauge and fuel warning indicator operation.
- Powertrain Control Module (PCM) to store Diagnostic Trouble Codes (DTCs) for mis-fire detection when the fuel level in the fuel tank is below a predetermined capacity.
North American Specification (NAS) and China (CN6) vehicles have a Diagnostic Module Tank Leakage (DMTL) pump for leak detection requirements. The DMTL has additional connections, hoses and pipes.
For additional information, refer to: EVAPORATIVE EMISSIONS
Fuel System Flow Schematic
| ITEM | DESCRIPTION |
|---|---|
| 1 | Left High Pressure (HP) fuel rail |
| 2 | Fuel Injector (quantity 6) |
| 3 | Right HP fuel rail |
| 4 | HP fuel pump (quantity 2) |
| 5 | Fuel line |
| 6 | Low fuel pressure sensor |
| 7 | Pressure Relief Valve (PRV) |
| 8 | Fuel level sensor A (active side) |
| 9 | Low Pressure (LP) fuel pump |
| 10 | Jet pump |
| 11 | Fuel level sensor B (passive side) |