Ecm Relay. Testing - BMW 5251 Service Manual

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Fuel Injection
ECM relay, testing
The engine control module (ECM) relay is energized via the
ECM and supplies battery positive
(B+)
power to many of the
engine management components and subsystems. If this re-
lay is faulty, the engine will not start.
CAUTIOI\C
Relay positions can vary. Be sure to confirm relay position by
identifying the wiring in the socket using the wiring diagrams
in ELE Electrical Wiring Diagrams.
NOTE-
The ECM relay is also referred to as the DME main relay.
ECM relay powers:
* ECM
Ignition coils
Fuel injection
Evaporative leak detection pump (5.2.1 only)
Idle air actuator
Camshaft sensors
Evaporative emissions valve
Hot film mass air flow sensor
Fuel pump relay
Oxygen sensor heaters
4
Working in right rear of engine compartment:
Release interior ventilation filter cover latch (A) and re-
move cover.
Release plastic locking tab (B).
Rotate duct inward (arrow) to unloclc from bulk head and
remove duct.
0
Release spring lock (C) to remove lower filter housing.
Slide filter housing away from inner fender to remove.
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Remove electrical box (E-box) cover fasteners and remove
cover.