BMW X5: Limp-Home Mode
If a fault is diagnosed in the system, such as e.g. failure of the high-pressure sensor, the fuel-supply control valve is de-energized; the fuel then flows via a so-called bypass into the rail.
In the event of HPI limp-home mode, turbocharging is deactivated by an opening of the wastegate valves.
Causes of HPI limp-home mode can be:
- Implausible high-pressure sensor values
- Failure of the fuel-supply control valve
- Leakage in the high-pressure system
- Failure of the high-pressure pump
- Failure of the high-pressure sensor
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Fig. 56: Identifying Limp-Home Mode Diagram
Fuel System Safety
Working on this fuel system is only permitted after the engine has cooled down. The coolant temperature must not exceed 40ºC. This must be observed without fail because otherwise there is a danger of fuel sprayback on account of the residual pressure in the high-pressure system.
When working on the high-pressure fuel system, take particular care to ensure conditions of absolute cleanliness and follow the work sequences described in the repair instructions. Even the tiniest contaminant's and damage to the screw connections on the high-pressure lines can cause leaks.
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Fig. 57: Identifying Fuel System Safety Label
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Fig. 58: Identifying High-Pressure Fuel Lines
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Piezo Fuel Injectors
It is the outward-opening piezo-injector that renders possible spray-directed
direct injection and thus the overall
innovations of the N54 engine. Due to the fact that only this component ensures
th
Piezo Element
The movement of the nozzle needle in the injector is generated no longer by a
solenoid coil but rather by a
piezo-element.
A piezo-element is an electromechanical converter, i.e. it consists of a ce
Ignition Management
Most of the ignition system components have remained the same for all NG6
engines for 2007. There are some
minor changes to the ignition coils that apply to all versions. The coils have
been optimiz
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Operating via the
Controller
Opening the main menu
Press the button.
The main menu is displayed.
Selecting a menu
Selecting menu items
1. Turn the Controller until the desired menu
item is highlighted.
2. Press the Controller.
Select a widget
1. Move the Controller in the main menu to the
right.
2. Turn the Controller until
Replacing Fluid In ABS/ASC+T Brake System
Necessary preliminary tasks:
Remove left microfilter housing cover.
Read and comply with General Information.
IMPORTANT: When carrying out repairs to the brake system, follow the
procedure set out in
Bleeding brake system with DSC.
Connect brake fluid changer to expansion tank and switch on.
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