BMW 3 (E46). Instruction - page 88

Note:
Replacement ECMs must be coded with
application information (i.e. engine
code, transmission type, etc.) prior to
installation. Consult an authorized
BMW dealer before replacing the ECM.
Alternatively, coded ECMs may be
available at an additional cost.
-
Disconnect negative (-) battery
cable. Wait at least three minutes.
CAUTION!
Prior to disconnecting the battery,
read the battery disconnection
cautions given at the front of this
manual on page viii.
-
Remove E-box cover at left rear of
engine compartment. Cover is
retained with four captive screws.
ECM (arrow) is located in right rear of
E-box, as identified with five electrical
harness connectors.
Disconnect ECM harness connectors
by releasing lock on each plug and
pivoting lever. Pull all five connector up
and off ECM.
-
Remove ECM from retaining
brackets and pull from its holder.

-
Installation is reverse of removal.

130-4
ECM Pin Assignments
ECM pin assignments are given in
Table b. ECM pin assignment-DME
MS 42.0 and MS 43.0
. This information
may be helpful when diagnosing faults
to or from the ECM. If all inputs and
wiring are OK but operational problems
still exist, the ECM itself may be faulty.
Generally, absence of voltage or
continuity means there is a wiring or
connector problem. Test results with
incorrect values do not necessarily
mean that a component is faulty.
Check for loose, broken or corroded
connections and wiring before
replacing components. If the results
are still incorrect, check the component
itself.
For engine management system
electrical schematics, see Electrical
Wiring Diagrams.
CAUTION!
Always wait at least three
minutes after turning off the
ignition before removing the
connector from the engine
control module (ECM). If the
connector is removed before
this time, residual power in the
system relay may damage the
ECM.
Always connect or disconnect
the control module connector
and meter probes with the
ignition off.
When making checks at the ECM itself,
a breakout box should be used to allow
tests to be made with the connector
attached to the ECM. This also
prevents damage to the small terminals

in the connector. As an alternative, the
harness connector housing can be
separated so that electrical checks can
be made from the back of the
connector.
Table b. ECM pin assignment-DME MS 42.0 and MS 43.0
Connector X60001 9-pin black
Pin
Signal
Component/function
Notes
1
Output
Terminal 15
Unloader relay terminal 15
2
not used
3
not used
4
Ground
Ground
Ground point
5
Ground
Ground
Ground connector
6
Ground
Ground
Ground connector
7
Input
Terminal 30 (Fuse 80
amp)
B+ Terminal
8
Input
Voltage supply (Fuse 2)
Fuse carrier, engine electronics
9
Input
Voltage supply
Fuse carrier, engine electronics
Connector X60002 24-pin black
Pin
Signal
Component/function
Notes
1
Input
Heater, precatalyst
oxygen sensor 1
Heated oxygen sensor 1 in
front of catalytic converter
2
not used
3
Input/output
CAN bus signal, low
Transmission control module
4
Input/output
CAN bus signal, high
Transmission control module
5
not used
6
Input/output
Transmit diagnosis line
(TXD) data link signal
Transmission control module
7
Input
Heater, post-catalyst
oxygen sensor 1
Heated oxygen sensor 1
behind catalytic converter
8
not used