865891T01 Mercruiser HARNESS ASSEMBLY, Fuel/Paddle, Fuel Tank/Paddle Wheel

Table 1
Operation of the 4-Pin Sensor
This sensor has two output terminals. The voltage on the terminals indicates the coolant level.
Condition Code Terminal on the P1 Connector
Suspect Parameter Number (SPN) Failure Mode Identifier (FMI) Code Description Output Terminal on the 4-Pin Sensor Voltage on the Terminal
Normal Coolant Level N/A D Minimum of 4.1 VDC P1-49
A Maximum of 0.5 VDC P1-54
Low Coolant Level 111 17 Engine Coolant Level : Low - Least Severe (1) D Maximum of 0.5 VDC P1-49
A Minimum of 4.1 VDC P1-54
Low Coolant Level 111 1 Engine Coolant Level : Low - Most Severe (3) This code is activated after the "low coolant level" condition has existed for a few seconds.
111 2 Engine Coolant Level : Erratic, Intermittent, or Incorrect This code is activated if both outputs are the same voltage for at least 2 seconds.
Table 2
Operation of the 2-Wire Float Sensor (1)
This sensor has one output terminal. The voltage on the terminal indicates the coolant level.
Condition Code Voltage Range (2) Terminal on the P1 Connector
Suspect Parameter Number (SPN) Failure Mode Identifier (FMI) Code Description
Normal Coolant Level N/A 0.8 VDC
to
1.8 VDC P1-26
Low Coolant Level 111 17 Engine Coolant Level : Low - Least Severe (1) 2.0 VDC
to
3.0 VDC
Low Coolant Level 111 1 Engine Coolant Level : Low - Most Severe (3) 3.3 VDC
to
4.3 VDC
111 3 Engine Coolant Level : Voltage Above Normal Voltage is greater than 4.5 VDC.
111 4 Engine Coolant Level : Voltage Below Normal Voltage is less than 0.5 VDC.
(1) There are two types of sensor that can be utilized when the ECM is programmed to this option. Some sensors will have 2 wires and some sensors will have 3 wires. A sensor with 3 wires requires 5 VDC to operate. The power wire for this sensor may be connected to terminal 2 of the P1 connector. The 2-wire float sensor does not require electrical power to operate.
(2) The voltage that is between the ranges is a hysteresis band. The hysteresis band will prevent false indications when the coolant sloshes in the tank.
Table 3
Operation of the 2-Pin Switch
This switch creates a short circuit when coolant is present.
Condition Code Condition of the Circuit
Suspect Parameter Number (SPN) Failure Mode Identifier (FMI) Code Description
Normal Coolant Level N/A Short circuit between P1-49 and sensor common
Low Coolant Level 111 17 Engine Coolant Level : Low - Least Severe (1) Open circuit between P1-49 and sensor common
Low Coolant Level 111 1 Engine Coolant Level : Low - Most Severe (3) This code is activated after the "low coolant level" condition has existed for a few seconds.
Illustration 1 g01118000
A typical schematic for the 4-pin sensor.
The return wire may be connected to P1-3, P1-5, or P1-18.
Probable Causes
Codes
Electrical connectors
Sensor supply voltage
Coolant level sensor
Wiring harness
ECMRecommended Actions
Table 4
Troubleshooting Test Step Value Result
1. Check for Codes
A. Establish communication between Cat® Electronic Technician (ET) and the engine ECM.
B. Access the "Active Diagnostic" screen.
C. Verify that a code for the coolant level switch is active.
Codes
Result: There is a 111-2 code. There is a problem with the circuit for the 4-pin sensor.
Proceed to Test Step 2.
Result: There is a 111-3 or 111-4 code. There is a problem with the circuit for the 2-wire float sensor.
Proceed to Test Step 8.
2. Inspect Electrical Connectors and Wiring for the 4-Pin Sensor
A. Thoroughly inspect the J1/P1 ECM connector, the connector for the extension harness for the coolant level, and the terminals for the coolant level sensor in the connectors.
Note: The connector for the extension harness for the coolant level connects the coolant level sensor to the vehicle harness in the engine compartment of some chassis. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
B. Perform a 45 N (10 lb) pull test on each of the wires in the ECM conn