2001 BMW 530i Evap system

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160 Fuel Tank and Fuel Pump
General ........................... .I6 0.2
Special tools ........................ .I6 0.2
Fuel pump ......................... .I6 0.3
Fuel tank evaporative control system ..... .I6 0.3
Evaporative system troubleshooting ..... .I6 0.4
Warnings and cautions ................ .I6 0.5
Fuel System Troubleshooting ...... .I6 0.6
Fuel pump fuse and relay .............. .I6 0.6
Operating fuel pump for tests ........... .I6 0.6
Fuel pump electrical circuit, testing ...... .I6 0.7
Fuel pump power consumption, testing ... .I6 0.9
Fuel pressure gauge, installing
(6-cylinder models)
................. .I6 0.1 0
Fuel pressure gauge, installing
(V-8 models) ....................... .I6 0.1 1
Fuel delivery, testing ................ .I6 0.12
Fuel Pump and Fuel Level Sender . . 160-15
Fuel level sender (right side) and
fuel pump. removing and installing
...... 160-15
Fuel level sender (left side).
removing and installing
............... 160-17
Siphon pump. removing and installing .... 160-1 9
Fuel Tank and Fuel Lines .......... 160-20
Fuel tank. draining ................... 160-20
Fuel tank. removing and installing ....... 160-21
Fuel expansion tank. removing
and installing
....................... 160-23
Activated carbon canister I fuel tank
leak detection unit
(LDP or DMTL).
removing and installing ............... 160-24
Running losses (312-way) valve.
removing and installing
............... 160-24

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Fuel Tank and Fuel Pump
Fuel pump
The electric fuel pump is mounted in the fuel tank in tandem
with the right side fuel level sender. The fuel pump delivers
pressurized fuel to the fuel injection system.
A pressure regu-
lator maintains system pressure. The quantity of fuel supplied
exceeds demand, so excess fuel returns to the fuel tank via a
return line. See
130 Fuel Injection for more information.
NOTE-
Fuel pump removal procedures are given under Fuel level
sender (right side) and fuel pump, removing and install-
ing.
Fuel tank evaporative control system
Evaporative control, also referred to as running losses con-
trol, is designed to prevent fuel system evaporative losses
from venting into the atmosphere.
The components of this system allow control and monitoring
of evaporative losses by the on-board diagnostic
(OED II)
software incorporated into the engine control module (ECM).
NOTE-
1997 V-8 models (540i) with Bosch DME M5.2 are not
equipped with an
OBD I1 running losses monitoring system.
Fuel tank evaporative
control system
(models with
DME MS42.0)
4 The main components of the evaporative control system and
their functions:
Fuel overflow
tank acts as a liquidlvapor separator
Carbon canister stores evaporated fuel.
Plumbing ducts vapors from fuel tank to canister and from
canister to intake
manifold.
- Carbon canister purge valve is controlled by enginecontrol
module (ECM).
Running losses or 312-way valve (not shown) shunts ex-
cess fuel volume directly
back to fuel tank before it circu-
lates through injector fuel rail (models with Siemens MS42
or Bosch M5.2.1 engine management only).
Leak detection unit (LDP or DMTL) pressurizes fuel
tank
and evaporative system to monitor system leaks (models
with Siemens MS42 or Bosch M5.2.1 and later).
Leak detection systems vary among models and years, and
are further described in
130 Fuel Injection.
NOTE -
"3/2-way valve", 'tunning losses valve" and "fuel changeover
valve" are used interchangeably
in BMW technical literature.

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Fuel Tank and Fuel Pump
Evaporative system troubleshooting
- Start by accessing diagnostic trouble codes (DTCs) using a
BMW or BMW compatible aftermarket scan tool.
For purposes of OBD
II emissions compliance, the DME
system sets a diagnostic trouble code (DTC) when it de-
tects a leak that is equal or larger than minimum
lealc
sensed by system.
Malfunction Indicator Light (MIL) is illuminated upon sec-
ond recurrence of fault. See OBD On-Board Diagnostics.
- When leak testing, observe following conditions to obtain
plausible results:
Fuel tank
'1, to 'I., full.
0 Vehicle parked for at least 2 hours to allow fuel to reach
room temperature.
Ideal fuel temperature is 10"- 20°C
(50"
- 68" F).
Do not refuel immediately before
lealc test.
- If a leak is detected, check the following areas:
* Fuel filter cap (leaking or off).
Fuel tank ventilation lines leaking at fuel
tank or activated
carbon canister.
i
Tank ventilation valve leaking (in engine compartment).
Fuel level
sensorlfuel pump cap leaking.
Evaporative system component replacement is covered later
in
th~s group in Fuel Tank and Fuel Lines.

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--
I Fuel Tank and Fuel Pump
The plastic fuel tank is mounted underneath the center of the
car (underneath the rear seat). Mounted in the fuel tank are
the fuel pump and fuel level sending units. Connecting lines
for the evaporative emission control system and expansion
tank are also attached to the tank.
Fuel
tank capacity for E39 models
Tank capacity
70 liters (18.5 gal)
Reserve capacity
8 liters (2.1 gal)
Fuel tank, draining
Drain fuel tank into a safe storage unit using an approved fuel
pumping device.
WARNING-
# Before removing tank, be sure that all hot components,
such as the exhaust system, are completely cooled down.
Fuel may be spilled. Do not smoke or
work near heat-
ers or other fire hazards.
- Start engine and allow to run 10 - 15 seconds to fill fuel com-
pensating siphon assembly. This will allow both lobes of fuel
tank to he drawn off through fuel filler pipe,
- Disconnect negative cable from battery.
CAUTION-
Prior to disconnecting the batteg read the battery discon-
nection cautions given
in 001 General Warnings and Cau-
tions.
- Remove fuel tank filler cap
- Slide suction hose into filler neck about 130 cm (51 in.), twist-
ing as necessary. Withdraw fuel into storage unit.
- Monitor fuel level reduction in both lobes:
- Remove rear seat cushion and access both fuel tank send-
er harness connectors.
Use multimeter to measure resistance at both senders,
Resistance should drop as fuel level drops.
- If siphoning mechanism is faulty, drain left tank lobe sepa-
rately by removing sender cover and pumping fuel directly
out of left lobe.

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OED-2
On-Board Diagnostics
Specialized OED II scan tool equipment is needed to access
the fault memory and
OED I1 data.
The extra hardware needed to operate the OED
I1 system
consists mainly of the following:
* Additional oxygen sensors downstream of the catalytic
converters.
Fuel tank pressure sensor and device to pressurize
fuel
storage system.
Several engine and performance monitoring devices
Standardized 16-pin
OED II connector under the
dashboard.
Upgraded components for the federally required reliability
mandate.
Malfunction indicator light (MIL)
OED II software illuminates the malfunction indicator light
(MIL) when emission levels exceed 1.5 times Federal
standards.
4 For E34 cars covered by this manual, three different MIL
symbols were used, depending on year and model.
MIL illuminates under the following conditions:
Engine management system fault detected for
two
consecutive OED iI drive cycles. See Drive cycle in this
repair group.
- Catalyst damaging fault detected.
Component malfunction causes emissions to exceed 1.5
times OED
II standards.
Manufacturer-defined specifications exceeded. Implausible input signal.
Misfire
faults.
Leak in evaporative system,
Oxygen sensors observe no purge
flow from purge valve 1
evaporative system.
ECM fails to enter closed-loop operation within specified
time.
ECM or automatic transmission control
module (TCM) in
"limp home" mode.
ignition key ON before cranking (bulb
check function).
OED
II fault memory (including the MIL) can only be reset
using a special scan tool. Removing the connector from the
ECM or disconnecting the battery does not erase the fault
memory.

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- -
On-Board Diagnostics
Professional diagnostic scan tools available atthe time of this
printing include the BMW factory tools
(DISplus, GTI,
MoDiC) and a small number of aftermarket BMW-specific
tools. See
020 Maintenance.
In addition to the professional line of scan tools, inexpensive
generic OBD
II scan tool software programs and handheld
units are readily available. Though limited, they are
nonetheless powerful diagnostic tools. These tools read live
data streams and freeze frame data as well as a host of other
valuable diagnostic data.
Diagnostic monitors
Diagnostic monitors run tests and checks on specific
emission control systems, components, and functions.
A complete drive cycle is requiredforthe tests to bevalid. See
Drive cycle in this repair group. The diagnostic monitor
signals the
ECM of the loss or impairment of the signal or
component and determines if a signal or sensor is faulty
based on
3 conditions:
* Signal or component shorted to ground
Signal or component shorted to
B+
Signal or component missing (open circuit)
The OBD
II system monitors all emission control systems that
are installed. Emission control systems vary by vehicle model
and year. For example, a vehicle may not be equipped with
secondary air injection, so no secondary air readiness code
would be present.
OBD
II software monitors the following:
Oxygen sensors
Catalysts
Engine misfire
- Fuel tank evaporative control system
Secondary air injection Fuel system
Oxygen sensor monitoring. When driving conditions allow,
response rate and switching time of each oxygen sensor is
monitored. The oxygen sensor heater function is also
monitored. The OBD
II system differentiates between
precataylst and post-catalyst oxygen sensors and reads each
one individually. In order
forthe oxygen sensor to be
effectively monitored, the system must be in closed loop
operation.

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OBD-6
On-Board Diagnostics
Fuel system monitoring. This monitor looks at the fuel
delivery needed (long
/short term fuel trim) for proper engine
operation based on programmed data. If too much or not
enough fuel is delivered over a predetermined time, a DTC is
set and the MIL illuminates.
Fuel trim refers to adiustments to base fuel schedule.
Lono- ., term fuel trim refers to gradual adjustments to the fuel
calibration adjustment as compared to short term fuel trim.
Long term fuel trim adjustments compensate for gradual
changes that occur over time.
Fuel system monitoring monitors the calculated injection time
(ti) in relation to enginespeed, load and precatalyticconverter
oxygen
sensor(s) signals.
Using this data, the system optimizes fuel delivery for all
engine operating conditions.
Evaporative system monitoring. This monitor checks the
the fuel storage system and related fuel lines for leaks. It can
detect very small leaks anywhere in the system.
A leak detection unit (LDP or DMTL) is used to pressurize the
evaporative control system on a continuous basis (as the
drive cycle allows) and to
check system integrity.
Drive cycle
The OED II drive cycle is an important concept in
understanding OBD
II requirements. The purpose of the drive
cycle is to run ail of the emission-related on-board diagnostics
over a broad range of driving conditions.
A drive cycle is considered complete when all of the
diagnostic monitors have run their tests without interruption.
~ora drive cycle to be initiated, the vehicle must be started
cold and brought up to
1 60°F and at least 40°F above its
original starting temperature.
Readiness codes
Inspection/maintenance (I/M) readiness codes are mandated
as part of OBD
II. The readiness code is stored aftercomplete
diagnostic monitoring of specified components and systems
is carried out. The readiness code function was designed to
prevent manipulating an
I/M emission test procedure by
clearing faults codes or disconnecting the ECM or battery.

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On-Board Diagnostics
Readiness codes indicate whether the OED Ii system is
actually ready to monitor the various emission control
systems on the vehicle. The vehicle must complete a drive
cycle to set readiness codes. The code is binary:
0 for ready
1 for not ready
f
4 The parameters which are monitored for readiness are:
llM readiness codes
1. Catalyst efficiency
2. Catalyst heating
3. Fuel tank evaporative control
4. Secondary air injection
5.
NC refrigerant
6. Oxygen sensors
7. Oxygen sensor heaters
8. Exhaust gas recirculation
Readiness codes are set to 1 (not ready) in the following
cases:
~9~~.f~[<+t~t~p:,~;:#j~~{]~y~ ,,... , , 8701Dbd001
The battery or ECM is disconnected.
When
all zeros are displayed, the system has established
DTCs are erased after completion of repairs and a drive
cycle is not completed.
readiness. Readiness codes
can be displayed using BMW
and aftermarket scan tools.
An
OED II scan tool can be used to determine IIM readiness.
Diagnostic trouble codes (DTCs)
SAE standard J2012 mandates a 5-digit diagnostic trouble
code (DTC) standard. Each digit represents a specific value.
Emission related DTCs
start with the letter P for power train.
When the engine service
light (MIL) is illuminated it indicates
that a DTC has been stored.
DTCs are stored as soon as they occur, whether or not the
engine service light illuminates.
DTCs store and display a time stamp.
DTCs record the current fault status: Present, not currently
present, or intermittent.