Installation Manual

Electrical & Electronic Application And Installation Manual
Production Release Version 1.0
Page 39
4.3.4 Correct method of ECM battery connection.
Correct Power Supply Wiring
• ECM Positive wires connected direct to battery, not via starter motor
• Power supply wires go to all 3 positive pins and all 3 negative pins on
the ECM Connector
• ECM Negative is wired to the battery rather than return through
chassis.
• The engine is grounded to the machine chassis.
This diagram is for discussion regarding 12V electrical systems, Items
such as circuit protection have been removed for clarity.
-
+
FRAME
Engine
Junction box
Starter
Alternator
Disconnect Sw
Engine ECM
Engine Gnd
Stud
Note A: Keep to a minimum distance
Note B: Keep to a minimum distance
Note C: Observe maximum resistance
Note D: Specify maximum number of terminals and maximum load
Note A + C
Note A + C
Note C
Note A + C
Note B + C
Note B
Note D
Junction blk
A
B
Note A
Note E: Case Ground or Strap Ground – Check Alternator Spec.
Note F: Starter motor grounding may be made through the machine
chassis as long as the total circuit resistance for 12V system does not
exceed 1.7mOhm and for 24V 3.4mOhm (1204 – 1206F).
Note F
Note A
Note E
Note G: The number of ECM supply and return connections varies
between engine families. Please refer to the ECM J1 connection list for
details on the number of connections required for each specific engine
range.
Note G
4.3.5 Incorrect method of ECM battery connection.
Incorrect wiring
• Positive wired via starter motor. High volt drop to ECM on starting
• Single pin on ECM used for each of positive and negative supply.
Possibly exceeding pin ratings and possible risk of arcing or
overheating.
• ECM return through chassis – risk of conducted noise and also
additional voltage drop.
• Engine not grounded – risk of engine component damage.