Ecm Relay. Testing - BMW 5251 Service Manual

Fuel Injection
1
Working in right rear of engine compartment:
Release interior ventilation filter cover latch (A) and re-
move cover.
Release plastic locking tab (6).
Rotate duct inward (arrow) to unlock from bulk head and
remove duct.
Release spring lock (C) to remove lower iilter housing.
Slide filter housing away from inner fender to remove.
-
Remove electrical box (E-box) cover fasteners and remove
cover.
NOTE-
OBD I1 fault memory (including an illuminated MIL) can
only be reset using an electronic scan tool. Removing the
connector from the ECM or disconnecting the battery will
not erase the fault memory.
The BMW-dedicated 20-pin diagnostic linlc connector
(DLC) is in the right rear of the engine compartment.
The 16-pin OBD I1 diagnostic connector (arrow) is located
inside the car on the lower left dash panel.
ECM relay, testing
Fuses lor ECM In E-bbx
502130488
4
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.
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.