Range Rover L322 User Manual download pdf (Page 80)

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DESCRIPTION AND OPERATION

RANGE ROVER 4.55

Coolant Valve

A single coolant valve is fitted on the ATC system to control coolant flow to the heater matrix.

The coolant valve (C2034) is controlled by a Pulse Width Modulated (PWM) signal from the

ATC ECU (C1629) on a YN wire.

Auxiliary Coolant Pump

The auxiliary coolant pump is used to ensure a satisfactory flow rate through the heater

matrix at low engine speeds. The ATC ECU (C1629) provides a feed to the pump (C2035)

on a UG wire. The pump (C2035) is earthed on an N wire.

Cooling Fan

Operation of the cooling fan is controlled by the ECM. When the compressor is engaged, the

ATC ECU (C1629) informs the ECM (C0331) via the K bus on a WRY wire that cooling fan

operation is required. The ATC ECU also informs the ECM of the speed at which the fan

should be driven.

The ECM also monitors Engine Coolant Temperature (ECT) to determine fan speed. The

ECM (C0606) provides a feed to the ECT sensor (C0169) on an SU (Td6) or YG (V8) wire.

The ECT sensor is a Negative Temperature Coefficient (NTC) sensor. By measuring the

voltage returned on an NG (Td6) or NO (V8) wire, the ECM can determine engine coolant

temperature.

The ECM (C0331) now provides a feed to the cooling fan control unit (C0005) on a BG wire.

This is used by the control unit to regulate the supply voltage from maxi fuse 61 of the

passenger compartment fuse box (C0581) on an RU wire.

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Comments to this Manuals

Lee 18 Apr 2024 | 04:50:09

Range Rover L322 User Manual Page 80

Comments to this Manuals