Mercury MerCruiser MCM 454 Mag MPI Service Manual page 694

SERVICE MANUAL NUMBER 23
Discrete Input Circuit Check - Non-Scan 7.4L MPI Only (4 of 5)
TESTING CIRCUITS FOR SHORT-TO-GROUND (–)
Index
90-861326--1 MARCH 1999
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STEP
1. Disconnect PUR wire from oil pressure
switch.
2. Disconnect TAN/WHT wire from gear
1 lube monitor.
3. Disconnect BLU/TAN wire from transmis-
sion temperature switch (if equipped).
4. Key "ON", engine "OFF".
Does audio warning buzzer sound?
1. Key "OFF".
2. Disconnect ECM J1 connector.
2
3. Check for continuity between all wires
disconnected in "Step 1" and engine ground (–).
Is there continuity on PUR wire?
Is there continuity on TAN/WHT wire?
Is there continuity on BLU/TAN wire?
3 Circuit(s) is not shorted to ground (–).
4 Repair short-to-ground (–) in affected circuit.
ACTION
GENERAL SYSTEM DIAGNOSTICS
VALUE YES NO
PROCEED TO
Step 2 Step 3
0 Ohms Step 4 Step 3
0 Ohms Step 4 Step 3
0 Ohms Step 4 Step 3
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Page 5E-101
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