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
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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
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Lane departure warning
Principle
The lane departure warning alerts when the vehicle
is about to run off the road or exit the lane.
General information
This camera-based system warns starting at a
minimum speed.
The minimum speed is country-specific and is
displayed in the menu for the intelligent Safety
systems.
Warning
Glass sunroof
General information
The glass sunroof and the sun protection are operated
using the same switch.
The glass sunroof can be opened from the outside
with the vehicle key and also closed with
Comfort Access.
With Comfort Access: The glass sunroof can be
closed from the outside via Comfort Access.
Safe
