Wire Color Code Abbreviations; Warning System Wiring Diagram; Troubleshooting Without A Computer Diagnostic System (Cds); Troubleshooting With Cds G3 - Mercury 15 EFI FourStroke Service Manual

Wire Color Code Abbreviations

BLK
BRN
GRN
PNK
RED
WHT
LT

Warning System Wiring Diagram

18 1
a
18 1
19 2
20 3
21 4
22 5
23 6
2
24 7
25 8
4
26 9
27 10
28 11
33
29 12
30 13
31 14
32 15
33 16
34 17
34 17

Troubleshooting without a Computer Diagnostic System (CDS)

Troubleshooting without a computer diagnostic system (CDS) is limited to checking resistance on some of the sensors.
Typical failures usually do not involve the ECM. Connectors, setup, or mechanical wear are most likely at fault.
• Verify the ignition coils are securely connected to the spark plugs.
• The engine may not run or may not run above idle with the wrong spark plugs installed.
• Swap ignition coils to see if the problem follows the coil or stays with the particular cylinder.
IMPORTANT: Disconnecting a sensor while the engine is running may result in a fault recording in the ECM Fault History. Use
the CDS to view the ECM fault history when troubleshooting/repair is completed.
• If all cylinders exhibit similar symptoms, the problem is with a sensor or harness input to the ECM.
• If a problem is speed related or intermittent, it is probably connector or contact related. Inspect connectors for corrosion,
loose wires, or pins pushed back into the connector. Verify the connectors are properly seated.
• Inspect the harness for damage: pinched or cut wires and chafing.
• Secure the grounds and all connections involving ring terminals. Apply Liquid Neoprene to all ring terminal connections.
Tube Ref No.
Liquid Neoprene
25
• Inspect the fuel pump electrical connector for corrosion, loose wires, or pins pushed back into connector.
• Check the fuel pump pressure.

Troubleshooting with CDS G3

The ECM is designed such that if a sensor fails, the ECM will prevent the engine from going into an overly rich condition. This
means that disconnecting a sensor for troubleshooting purposes may have no noticeable effect, presenting the technician with
a difficult diagnostic challenge. To meet this challenge, Mercury Marine has developed the CDS G3 diagnostic tool.

About CDS G3

CDS G3 is a standalone program that provides diagnostic support for select Mercury engines and engine control systems.
CDS G3 also supports all configuration functions necessary for preparing these systems for delivery. CDS G3 provides a clean,
easy‑to‑navigate interface.
90-8M0125265 eng NOVEMBER 2017
Wire Color Abbreviations
Black
Brown
Green
Pink
Red
White
Light
J6
YEL
BLU
LT GRN
Description
BLU
GRA
ORN
PPL
TAN
YEL
DK
b
BLU 1
YEL 2
J1
WHT/RED
c
LT GRN
62885
Where Used
All ring terminal connections
© 2018 Mercury Marine
General Troubleshooting
a - Engine control module (ECM)
b - Warning horn
c - Warning light
J1
Blue
Gray
Orange
Purple
Tan
Yellow
Dark
Part No.
92- 25711 3
Page 1E-7