Engine Cooling: Other Land Rover Freelander I рестайлинг

COOLING FANS

The cooling fans are variable speed electric fans installed in a housing attached to the rear of the radiator. The motor of each cooling fan is connected to a cooling fan ECU, located on the rear of the cooling fan housing. The cooling fan ECU is controlled by the Engine Control Module (ECM). The ECM controls the operation of cooling fans via a Pulse Width Modulated (PWM) signal to the cooling fan ECU. The cooling fan ECU regulates the voltage of a common power feed to the 2 fans, and relates the voltage to the duty cycle of the PWM signal.

Cooling Fan Control

The ECM varies the duty cycle of the PWM signal between 3-90 percent to vary cooling fan speed. The cooling fans are off at duty cycles between 3-9 percent. When duty cycle increases above 9 percent the cooling fans come on at minimum speed. The speed increases in proportion to increase in duty cycle, up to a maximum speed at a duty cycle of 90 percent. If duty cycle is less than 3 percent or more than 90 percent, the cooling fan ECU interprets the signal as an open or short circuit and runs the cooling fans at maximum speed to ensure the engine and transmission do not overheat.

The speed of the cooling fans varies between a minimum of 750 RPM at 6 volts and a maximum of 4000 RPM at nominal battery voltage. To reduce the noise from the cooling fans they are driven at slightly different speeds, except when running at minimum or maximum speeds. Stepped speed changes occur at 1500 RPM (right cooling fan) and 1450-2600 RPM (left cooling fan) to improve refinement.

Control Inputs

While the engine is running, the ECM adjusts the speed of the cooling fans in response to inputs from

1. The thermostat monitoring sensor, for engine cooling. The fans come on at minimum speed if the coolant temperature goes above 194°F (90°C), and progressively increase to a maximum speed at a coolant temperature of 216°F (102°C).
2. The A/C system, via the instrument pack and the CAN bus, for refrigerant system cooling.
3. The Electronic Automatic Transmission (EAT) ECU, via the CAN bus, for transmission cooling.

If there is a conflict between requested cooling fan speeds from the different inputs, the ECM adopts the highest requested speed.

As part of the power down routine, when the ignition is turned off, if the ambient air temperature is more than 59°F (15°C) the ECM samples the coolant temperature using the input from the Engine Coolant Temperature (ECT) sensor. If the coolant temperature is more than 223°F (106°C), the ECM signals for the cooling fans to come on. The speed of the cooling fans is in proportion to the coolant temperature, from minimum speed at less than 223°F (106°C) to maximum speed at 239°F (115°C). The cooling fans are turned off after 5 minutes or when the coolant temperature decreases to 223°F (106°C), whichever occurs first.

Motor Protection

The cooling fan ECU monitors the speed of the cooling fans, from the current draw of the motors, and incorporates strategies to protect the motors from electrical overload if the fans are seized or heavily loaded (e.g. by debris or during wading).

When the duty cycle of the PWM signal indicates the cooling fans should be turned on, the cooling fan ECU initially outputs 2.5 volts to the motors to produce a SOFT start. When the cooling fan ECU detects the motors are running satisfactorily, it then increases the outputs to the appropriate voltages for the required cooling fan speeds. If a motor fails to start within 3 seconds, the cooling fan ECU turns off the output to the affected motor, waits for 5 seconds and then tries another SOFT start. If the second soft start fails, after a further wait of 5 seconds the cooling fan ECU outputs 6 volts to the motor in an attempt to get it started. If the motor starts, the cooling fan ECU then increases the output to the appropriate voltage for the required cooling fan speed. If the motor fails to start within 4 seconds, the cooling fan ECU turns the output off, then, provided the cooling fans are still requested on, periodically invokes the start routine in an attempt to get the motor running.

If a cooling fan is already running and then seizes or becomes heavily loaded, the cooling fan ECU turns off the output to the affected motor, then periodically invokes the start routine, while the cooling fans are still requested on, in an attempt to get the motor running again.

When one of the cooling fans is not running, the cooling fan ECU runs the other cooling fan at maximum speed.

Power Distribution

Feed from the positive battery terminal connector C0192 (Red wire) is supplied to MAXI fuse No. 61 and fuses No. 12 and 53 of the passenger compartment fuse box (C0632). Fuse No. 12 (C0586) provides a constant battery feed to the Heating, Ventilation and Air Conditioning (HEVAC) ECU (C1630) on a Red/Purple wire. MAXI fuse No. 61 (C0581) provides a constant battery feed to the cooling fan ECU (C0005) on a Red/Blue wire. Fuse No. 53 (C0583) provides a constant battery feed to the ignition switch (C0028) a Red wire. When the ignition switch is turned to the RUN position, current flows across switch (C0028) to fuse No. 34 located in the passenger compartment fuse box (C0585) on a Green wire. Fuse No. 34 (C0587) provides an ignition feed to the HEVAC ECU (C1629) on a Green/Yellow wire. See WIRING DIAGRAMS .

DISCONNECTING & CONNECTING BATTERY

1. Before disconnecting battery negative cable it is imperative that ignition key be removed from ignition switch. After removing ignition key WAIT at least 2 minutes before disconnecting battery negative cable. Failure to do so could result in navigation computer hardware damage and/or incorrect fuel gauge reading. Before disconnecting battery, disable alarm system and turn off all electrical equipment.
2. After reconnecting battery negative cable, the steering wheel must be turned to full left and right lock (with engine running). This allows Dynamic Stability Control (DSC) system to relearn steering wheel position. Failure to do so will result in a variety of instrument warning lights being illuminated.

Output To Cooling Fan ECU - Open Circuit Or Short To Ground

1. Possible Causes ECM connector C0331 or cooling fan ECU connector C1680. Open between ECM connector C0331 terminal No. 4 (Blue/White wire) and cooling fan ECU connector C1680 terminal No. 1 (Blue/White wire). Short to ground at ECM connector C0331 terminal No. 4 (Blue/White wire). Faulty cooling fan ECU. Faulty ECM.
2. Connectors Ensure ECM connector C0331 and cooling fan ECU connector C1680 are correctly latched and do not have backed out, damaged or corroded pins. See «WIRING DIAGRAMS»(ref-167962-S37819141182004102600000) . Repair as necessary. If okay, go to next step.
3. Open Check for an open between ECM connector C0331 terminal No. 4 (Blue/White wire) and cooling fan ECU connector C1680 terminal No. 1 (Blue/White wire). Repair as necessary. If okay, go to next step.
4. Short Check for a short to ground at ECM connector C0331 terminal No. 4 (Blue/White wire). See «WIRING DIAGRAMS»(ref-167962-S37819141182004102600000) . Repair as necessary. If okay, go to next step.
5. Other Possible Causes A faulty ECM or a cooling fan ECU. There is no testing available for ECM or cooling fan ECU.

Output To Cooling Fan ECU - Short To Battery Voltage

1. Possible Causes Short to battery voltage in signal link at cooling fan ECU connector C1680 terminal No. 1 (Blue/White wire). Faulty cooling fan ECU. Faulty ECM.
2. Short To Battery Voltage Measure voltage at cooling fan ECU connector C1680 terminal No. 1 (Blue/White wire). See «WIRING DIAGRAMS»(ref-167962-S37819141182004102600000) . If voltage is more than 6 volts, repair short to battery voltage as necessary. If voltage is 0-6 volts, go to next step.
3. Other Possible Causes A faulty ECM or a cooling fan ECU. There is no testing available for ECM or cooling fan ECU.

Cooling Fan Link Malfunction - Open Circuit Or No Signal

1. Possible Causes ECM connector C0331 or cooling fan ECU connector C1680. Open between ECM connector C0331 terminal No. 4 (Blue/White wire) and cooling fan ECU connector C1680 terminal No. 1 (Blue/White wire). Short to ground at ECM connector C0331 terminal No. 4 (Blue/White wire). Short to battery voltage in signal link at cooling fan ECU connector C1680 terminal No. 1 (Blue/White wire). Faulty cooling fan ECU. Faulty ECM.
2. Connectors Ensure ECM connector C0331 and cooling fan ECU connector C1680 are correctly latched and do not have backed out, damaged or corroded pins. See «WIRING DIAGRAMS»(ref-167962-S37819141182004102600000) . Repair as necessary. If okay, go to next step.
3. Open Circuit Measure resistance between ECM connector C0331 terminal No. 4 (Blue/White wire) and cooling fan ECU connector C1680 terminal No. 1 (Blue/White wire). If resistance is greater than one megohm, repair as necessary. If okay, go to next step.
4. Short To Ground Measure resistance between ground and ECM connector C0331 terminal No. 4 (Blue/White wire). See «WIRING DIAGRAMS»(ref-167962-S37819141182004102600000) . If resistance is less than 5 ohms, repair as necessary. If okay, go to next step.
5. Short To Battery Voltage Measure voltage at cooling fan ECU connector C1680 terminal No. 1 (Blue/White wire). See «WIRING DIAGRAMS»(ref-167962-S37819141182004102600000) . If voltage is more than 6 volts, repair short to battery voltage as necessary. If voltage is 0-6 volts, go to next step.
6. Other Possible Causes A faulty ECM or a cooling fan ECU. There is no testing available for ECM or cooling fan ECU.