BMW 3 (E46). Manual — part 80

Remove knock sensor mounting
bolts (A) on side of cylinder block.
Remove sensors.

CAUTION!

Note the installed angle of the knock
sensor on the block before removing
it. Reinstall the sensor in the same
position. Be sure to use a torque
wrench when tightening the sensor
mounting bolt.

Clean knock sensor contact surface on
engine block and sensor (arrows)
before installing knock sensor.

Tightening torque

Knock sensor to
cylinder block

20 Nm (15 ft.

lbs.)

-

Use scan tool to read out and clear
ECM fault memory.

130-1

General

This repair group covers service and
repair for the Siemens engine
management systems used on the E46
models covered by this manual.
Additional engine management
information may also be found in the
following repair groups:

100 Engine–General

120 Ignition System

160 Fuel Tank and Fuel Pump

Electrical Wiring Diagrams

Note:

Fuel pressure testing and fuel pump
repair information is covered in

160

Fuel Tank and Fuel Pump

.

Table a. Engine management
systems

Model Year:
Engine code

DME system

1999 - 2000:
M52 TU B25
M52 TU B28

Siemens MS 42.0

2001:
M54 B25
M54 B30

Siemens MS 43.0

The Siemens systems are
sophisticated self-diagnosing OBD II
systems. These systems continuously
monitor components and record and
store valuable diagnostic information.

When faults arise, or if the MIL

(malfunction indicator lamp) in the
instrument cluster is illuminated, begin
troubleshooting by hooking up a
BMW-compatible scan tool. The rich
diagnostic capabilities of these systems
have the potential to save hours of
diagnostic time, incorrect component
replacement and possible damage to
system components. See

OBD On

Board Diagnostics

at the back of this

manual.

Tools and test equipment

If the equipment required to do the job
is unavailable, it is recommended that
these repairs be left to an authorized
BMW dealer or other qualified BMW
repair facility.

Fuel pressure gauge Baum 1318
(Source: Baum Tools Unlimited)

Automotive digital multimeter Fluke 87

Low current test light (“noid”) Baum
1115a (Source: Baum Tools Unlimited)

Factory DTC scan tool BMW
DIS/MoDiC

Fuel line plugs BMW 13 5 281 / 13 5
282

Aftermarket DTC scan tool Baum
CS2000 (Source: Baum Tools
Unlimited)

Fuel line clamp BMW 13 3 010

Fuel rail to pressure gauge fitting BMW
13 5 220

Note:

Professional diagnostic scan tools
available at the time of this
printing include the BMW factory
tools (DISplus and MoDiC) and a
small number of aftermarket
BMW-specific tools. The `CS2000'
from Baum Tools Unlimited, the
`Retriever' from Assenmacher
Specialty Tools, and the MT2500
from Snap-on are three examples