The purpose of the Engine Coolant Level (ECL) monitoring system is to signal the driver in the event of a low coolant situation. Depending on the programming of the control module it is also capable of shutting off the engine to prevent damage to the engine due to low coolant level. See Figure
“Engine Coolant Level System Function”
.
Figure 1. Engine Coolant Level System Function
Section 25.1.1
Coolant Level Sensor
There are two types of coolant level sensors:
- Magnetic switch
- Conductive probe
The magnetic switch type sensor is used and located in plastic surge tanks. The magnetic switch will be open when the coolant level in the tank is full.
The conductive probe type sensor is used and located in steel surge tanks. The conductive probe is grounded when the coolant level in the tank is full. See Figure
“Coolant Level Sensor in Coolant Tank”
.
Figure 2. Coolant Level Sensor in Coolant Tank
For coolant level sensor wiring troubleshooting, see Figure
“Recommended Wiring for the Coolant Level Sensor”
.
Figure 3. Recommended Wiring for the Coolant Level Sensor
Section 25.1.2
Fault Detection Management
There are no ECM diagnostics for the ECL system. Flash Code 323 will be active when a low coolant situation is present, and the Pro-Link will indicate engine coolant below warning/critical level. After the coolant has been restored to proper levels, Flash Code 323 will remain as an inactive code and the ECM will log the engine hours of the occurrence. Fault code descriptions are listed in Table
“Fault Codes”
.
| Code | Fault Code Description |
| 236 | ECM has detected an open or shorted circuit on the ECL circuit. |
| 323 | The 5 volt circuit at pin #10 of the ECM has been pulled to ground, indicating low coolant. Check the cooling system. |
Section 25.1.3
Description
The ECL sensor is used with the optional engine warning and protection feature. The purpose of the coolant level system is to monitor the level of the coolant in the surge tank to protect the engine from damage due to operating the engine when the coolant level is low. Since this is an optional feature, the system functions by programming three-way warning or three-way engine shutdown in the control module.
Section 25.1.4
Coolant Level Sensor
There are two different types of sensors used in the coolant level monitoring system. One type is used in plastic surge tanks, and the other in steel surge tanks.
Section 25.1.5
Plastic Surge Tanks
Plastic surge tanks use a floating ball with a magnet and magnetic switch. With the coolant level full, the float will raise and the magnet will pull the level switch open. This will allow 5 volts to be present at pin No. 10 of the ECM. If the level should go low, the switch will close and pin No. 10 of the ECM would go to 0 volts. The ECM must be programmed for a plastic tank for this coolant level switch to operate properly.
Section 25.1.6
Steel Surge Tanks
Steel surge tanks use a conductive probe that allows the probe to be grounded when the coolant level is full. This causes the voltage at pin No. 10 to be 0 volts. If the coolant level is low, the probe circuit is open and a 5 volt signal is present at pin No. 10 of the ECM, indicating low coolant. If using a steel surge tank, it is necessary for the ECM to be programmed for a steel tank.
Section 25.1.7
Programming
Coolant level monitoring is a customer programmable feature that may be programmed by the EST using the customer password. Coolant level feature is operational if programmed for three-way warning or three-way shutdown. However, if not pre-programmed for three-way shutdown at the factory, it will not be possible to enable the shutdown feature.
Section 25.1.8
Flash Codes
The following flash codes could display when troubleshooting the ECL system.
Section 25.1.8.1
Flash Code 236
ATA Code PID 111 FMI 33
ECM: Engine coolant below warning/critical level
Flash Code 236 will be active when the ECM detects an in-range voltage error in the ECL circuit. The probable cause for this condition will be a high resistance connection or intermittent short to ground in the circuit.
Section 25.1.8.2
Flash Code 323
ATA Code PID 111 FMI 33
ECM: Engine coolant below warning/critical level
Flash Code 323 will be active when a low coolant situation is present and the EST will indicate COOLANT LOW. After the coolant has been restored to proper levels, Flash Code 323 will remain as an inactive code and the ECM will log the engine hours and odometer reading at the time of the occurrence.
Section 25.1.9
Troubleshooting
Use the EST to monitor the coolant level on the data list or to retrieve fault codes from the fault code list. Also prior engine events can be retrieved using the EST in the calibration data screen under the Event Log. This will display the total number of times the event has taken place, the engine hours, the odometer reading at which the last two events have taken place.
Section 25.1.10
Before Troubleshooting
Perform these steps before troubleshooting the ECL system:
- Ensure the batteries are fully charged. Check the battery connections and grounds for clean, tight connections, free of damage. Voltage tests will give misleading readings if batteries are not fully charged.
- Before troubleshooting a particular circuit, inspect connectors for pushed back, loose or damaged (spread or bent) terminals or wires with cut strands, etc. The wires and connections must be free of damage or corrosion. When some connectors corrode, a light white residue will be present. This must be removed.
- Inspect suspect circuit grounds for clean, tight connections, free of damage.
| Series 40E Troubleshooting Manual – 6SE241 |
| Generated on 10-13-2008 |