HEVAC 2 (NGRR) - System Overview
Fitted to all L322 Range Rovers, this system controls all heating and ventilation and is very flexible in respect of settings options.
SM062 - HEVAC 2 (NGRR) - System Help file
Version 1.27

HEVAC 2 (NGRR) - Known Fitments
Vehicle makes, models and variants known or believed to be using this vehicle system, required diagnostic lead and degree of known compatibility.

Vehicle Make Vehicle Model Vehicle Variant Diagnostic Lead
Land Rover Range Rover MK III ( L322) 2002 - 2009 Black OBDII Lead/LD020/LD021

HEVAC 2 (NGRR) - Physical Details

SM062 - HEVAC 2 (NGRR) - Diagnostic Capabilities (Read Fault Codes)
Reads the fault code memory. The ECU can self detect up to 68 different problems with itself, its wiring and its associated sensors, storing the respective code if it detects any malfunction or reading outside of pre defined acceptable limits. Not all stored faults may cause the fault warning lamp to illuminate.

SM062 - HEVAC 2 (NGRR) - Diagnostic Capabilities (Clear Fault Codes)
Clears the fault code memory.

SM062 - HEVAC 2 (NGRR) - Diagnostic Capabilities (Settings)
Values, configuration settings, and other stored information which can be read from the ECU, edited and then rewritten back. Read settings can also be stored as a standard HTML page for reference. These pages can then later be re loaded and re written back to the ECU. Please note that some values may be read only due to the fact that they are supplied from the ECUs ROM or are internally calculated.

  • Part Number: This is the manufacturer's part number for the ECU.
  • Hardware number: This is the hardware version which denotes the processor and circuit board type.
  • Software number: This denotes the coding inside the processor for the hardware.
  • Supplier number: This is a number which defines the supplier using a standard look up list of supplier ECU manufacturer numbers.
  • Coding index: This is the coding identification for the programming maps.
  • Diagnostic index: This is a number that indicates the diagnostic capabilities support level.
  • Bus index: This is a number that indicates the bus communication support level, the vehicle communication buses.
  • Week of Build: This is the week in which the unit was built.
  • Year of Build: This is the year in which the unit was built.
  • Auto recirculation time: This is a time period in minutes with choices of 6 min of 30 min that denotes how long the HEVAC system will enter auto recirculation for. The 30 min period is designed for hotter countries.
  • Country: This requires to be set to US for US specification vehicles otherwise it is set to the Rest of World.
  • Drive: Left hand drive or right hand drive.
  • Autoflap Program: This alters the positioning of the flap specifically for hot countries otherwise Other should be selected.
  • Seat Heating Temperature: This is the thermostatic point at which the seat heaters turn off. When set to LOW it is between 37 and 42 C, when set to HIGH it is between 39 to 44 C.
  • Set Point Offset: The options are plus(+) 1 degree or none. When plus 1 degree is selected the temperature which is set by the HEVAC system is actually 1C higher than that displayed. This is designed for compensation in hot countries where no offset is required.
  • Rear Blower Speed: This affects the maximum voltage supply to the rear blower motor and for hot countries HIGH should be selected otherwise LOW.
  • Forced Recirculation Mode: This alters the parameters that the ECU uses to determine when to enter the automatic recirculation mode. Hot countries specifically refer to the US, Canada, Gulf countries etc and everything else counts as Rest of World (other).
  • Defrost Mode: The NORMAL mode forces the heating ventilation controller to use its standard defrost programming. The COMBINED mode makes it use the heated front screen and heated rear screen also.
  • Park Fuel Burning Heating: This denotes if the fuel burning heater fitted has a control via the internal information system or through remote control.
  • Auxiliary Fuel Burning Heating: This denotes if the fuel burning heater is fitted or not.
  • Recirculation Memory: enabled or disabled - ENABLED this means that the recirculation flaps will stay closed at the ignition off which will prevent humid air entering the car in hot countries and DISABLED means that they will be left open to allow for ventilation.
  • Fuel Type: Choice of either petrol or diesel.
  • Number of Cylinders: options of 4, 6, 8 or 12.
  • Disable Compressor: This option is used when the HEVAC is set on the vehicles which do not have an air conditioning compressor.
  • Save on Ignition Off: This denotes when enabled that the HEVAC ECU will remember the settings and save them when the ignition is turned off to reuse them when the ignition is turned on other than resetting them when it is disabled.
  • Engine Temperature Limits: This denotes if the air conditioning shuts down when the engine temperature reaches 95 C.
  • Heated Screens Cut Off: When enabled this allows 3 minutes operation of front and heated screens before they automatically cut off due to low voltage.
  • Fan Blower Map: This controls the operation of the blower map whether it is the normal blower map or the special Japan blower map which is contained in the HEVAC ECU.
  • Solar Sensor: This denotes if the solar sensor is fitted or not. The low line HEVAC ECUs do not have a solar sensor.
  • Load Compensation: This denotes if load compensation information is transmitted to the engine management. It is ENABLED for diesel engines and DISABLED for all other variants.
  • Stepper Overrun: Allows stepper motors to overrun or not with or without causing a fault code.
  • Compressor Type: Either fixed displacement which is the type used on the Range Rover, or variable displacement which is the type used on some other cars.
  • Front Heated Screen: This denotes if the front heated screen is fitted or not.
  • Front Heated Seats: This denotes if the front heated seats are fitted or not.
  • Undervoltage: This denotes if undervoltage detection is enabled or not.
  • Temperature Control Map: This is a map of 12 hexadecimal numbers which control the temperature characteristics of the HEVAC control unit.
  • Coding Data: A specific block of programmable data stored in the ECU to control its functionality for specific variations of vehicle. There are a number of hexadecimal digits, each digit separated by a comma. Re-entered parameters should be entered in an identical format to that which is read. Changing these values can produce unknown alteration in the functionality of the ECU, damage the ECU, or even damage your car.

SM062 - HEVAC 2 (NGRR) - Diagnostic Capabilities (Inputs)
Realtime live display of the information the electronic control unit of the selected vehicle system is currently deriving from its input sensors.

BUTTONS AND LED
  • Coolant Temperature: This is the current engine coolant temperature in degrees centigrade.
  • Heated Washer Jet Status: This denotes if the heated washer jet is on or not.
  • Auxiliary Water Pump Switch: This shows if the auxiliary water pump switch is on or not.
  • Auxiliary Water Pump Status: This shows if the auxiliary water pump output is on or not.
  • Compressor Clutch: This denotes if the compressor clutch is on or off.
  • Compressor Relay: This shows if the compressor relay is on or not.
  • Heated Wash Switch: This denotes if the heated wash switch is on or not.
  • Recirculation Button: Denotes if the recirculation button is pressed or not.
  • Manual Recirculation LED: Denotes if the manual recirculation LED is on or not.
  • Auto Recirculation LED: Denotes if the auto recirculation LED is on or not.
  • Auto Function LED: Denotes if the auto function LED is on or not.
  • Auto Button: Denotes if the auto button is pressed or not.
  • Blower Positions 1 to 7 LED: Denotes if the blower positions 1 to 7 LED is on or not.
  • Auto Blower LED: Denotes if the auto blower LED is on or not.
  • Max LED: Denotes if the max LED is on or not.
  • Max Button: Denotes if the max button is pressed or not.
  • Program LED: Denotes if the programme LED is on or not.
  • Program Button: Denotes if the prog button is pressed or not.
  • Feet Blower LED: Denotes if the feet blower LED is on or not.
  • Feet Blower Button: Denotes if the feet blower button is pressed or not.
  • AC LED: Denotes if the air condition LED is on or not.
  • AC Button: Denotes if the air conditioning button is pressed or not.
  • Screen Blower LED: Denotes if the screen blower LED is on or not.
  • Screen Blower Button: Denotes if the screen blower button is pressed or not.
  • Face Blower LED: Denotes if the face blower LED is on or not.
  • Face Blower Button: Denotes if the face blower button is pressed or not.
  • Right Heated Seat Button: This denotes if the right heated seat button is pressed or not.
  • Right Heated Seat Status: Denotes if the right heated seat is on or not.
  • Right Hand Heated Seat Level 1 and 2 LED: Denotes if the right hand heated seat level 1 or 2 LED is on or not.
  • Left Heated Seat Button: This denotes if the left heated seat button is pressed or not.
  • Left Heated Seat Status: Denotes if the left heated seat is on or not.
  • Left Hand Heated Seat Level 1 and 2 LED: Denotes if the left hand heated seat level 1 or 2 LED is on or not.
  • Heated Rear Screen LED: Denotes if the heated rear screen LED is on or not.
  • Heated Rear Screen Status: Shows if the heated rear screen is on or not.
  • Heated Rear Screen Button: Denotes if the heated rear screen button is pressed or not.
  • Fuel Burning Heater Enable: Denotes if the fuel burning heater is on or not.
  • Heated Front Screen LED: Denotes if the heated front screen LED is on or not.
  • Heated Front Screen Status: Shows if the heated front screen is on or off.
  • Heated Front Screen Button: Denotes if the heated front screen button is pressed or not.
  • Park Heating Status: Denotes if the park heating is on or not.
AIR CONDITIONING VALUE INPUTS
  • LH Heat Exchanger: This is the air temperature just after the left hand heat exchanger. Normally expected values are from 5 C to 115 C.
  • RH Heat Exchanger: This is the air temperature just after the left hand heat exchanger. Normally expected values are from 5 C to 115 C.
  • Left/Right Hand Seat Temperature: This is the current temperature of the left/right hand seat.
  • Front Blower: This is the percentage of power that the front blower fan is set to.
  • Rear Blower: This is the setting for the rear blower motor in percentage.
  • Rear Temperature Setting: This is the temperature setting for the rear heater control in percentage. 100% is cold and 0% is hot.
  • Refrigerant Pressure: This is the refrigerant gas pressure in bar.
  • Right/Left Seat Heater Power: This is the percentage of power being applied to the right/left seat heater as a percentage.
  • Front Blower Monitor: This is the feedback in percentage that the front blower motor is attaining. This should match the front blower identically.
  • Rear Blower Monitor: This is the feedback in percentage that the rear blower fan is attaining.
  • Ambient Temperature: This is the vehicle's external temperature in C.
  • Cabin Temperature: This is the vehicle's internal cabin temperature in C.
  • Evaporator Temperature: This is the heating and ventilation systems evaporator temperature in C. Expected values of minus (-) 10 C to plus (+) 30 C.
  • Left Temperature Setting: This is the temperature setting for the left control in C.
  • Right Temperature Setting: This is the temperature setting for the right control in C.
  • Road Speed: This is the vehicle's current road speed in kilometres per hour and miles per hour.
  • LH/RH Water Valve Open Time: This is the pulse width modulation duration in milliseconds that the left/right hand water valve is open for.