Heating Output And Temperature Door Actuation, Checking, Vehicles Without A/C System
Refer to INFORMATION ON CHECKING HEAT OUTPUT AND TOOLS REQUIRED .
Test Requirements
- Coolant Circuit Bled According To Specifications. Refer to COOLANT CIRCUIT FILLING AND BLEEDING [CRUA, DEJA] / COOLANT, FILLING (BLEEDING) [CNSB, CNTC] .
- All air guides, covers and seal OK and properly installed
- Seal between engine compartment, engine hood and plenum chamber is OK and installed correctly. To check. Refer to COOLANT CIRCUIT FILLING AND BLEEDING [CRUA, DEJA] / COOLANT, FILLING (BLEEDING) [CNSB, CNTC] / OVERVIEW - PLENUM CHAMBER COVER / PLENUM CHAMBER COVER, REMOVING AND INSTALLING ; (Plenum Chamber Cover Overview).
- If installed: the After-Run Coolant Pump -V51- / Heater Support Pump -V488- (different designations, depending on the engine) and the Coolant Shut-Off Valve -N82- function are OK.
- The air flow through the dust and pollen filter is not affected by dirt in the filter. To check. Refer to DUST AND POLLEN FILTER, REMOVING AND INSTALLING .
- The air intake for the heater (in fresh-air and recirculated-air modes) is not affected by dirt or retrofitted components.
- The vehicle is not exposed to sunlight.
- Engine is warm: coolant temperature is greater than 80 °C (176 °F).
- The DTC memory for the Heater Control Module -J65- control head was checked and erased and the basic setting was performed. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
- The coding and adaptation of the Heater Control Module -J65- control head was checked. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
- Vehicles with a TDI engine: The actuation and function of the Auxiliary Heater Heating Element -Z35- is OK. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
- Vehicles with a gasoline engine and an Auxiliary Heater Heating Element -Z35- (introduction not yet finalized): The actuation and function of the Auxiliary Heater Heating Element -Z35- is OK. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
- Vehicles with a parking heater: actuation and function of the parking heater is OK. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
Checking
-- Close the engine hood, doors, windows and sunroof.
-- Open all instrument panel vents.
-- Start the engine and adjust the following settings on the Heater Control Module -J65- control head:
- Turn the temperature regulator -1- to the "cold" stop.
- Turn the air distribution knob -4- to the "instrument panel vent" stop.
- Turn the fresh air blower regulator -5- to the maximum speed.
-- Measure the ambient temperature.
-- Measure the temperature of the air coming out of the left and right instrument panel vents with a thermometer.
Target Values:
- After five minutes the measured values must be a maximum of 15 °C (59 °F) greater than the measured ambient temperature.
- The temperature deviation between the left and right side is less than 8 °C (46.4 °F).
If the specified values are not reached, check the following:
- Check the seal between the engine compartment, engine hood and plenum chamber and repair if necessary. Refer to OVERVIEW - BULKHEAD / OVERVIEW - PLENUM CHAMBER COVER ; (Plenum Chamber Cover Overview).
- Repeat the test while measuring the temperature of air drawn in via the fresh air intake for the heater in the plenum chamber with one of the two temperature sensors with the engine hood closed. The permissible increase of air temperature in the heater (between the air inlet in the fresh air intake and the air outlet from the instrument panel vents) is a maximum of 10 °C (50 °F).
If the temperature in the heater increases more than 10 °C (50 °F), check the following:
- Actuation and function of the Temperature Regulator Door Motor -V68- using the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
- Function of the temperature door in the heater. Refer to OVERVIEW - AIR DISTRIBUTION HOUSING DOORS AND PARTITIONS .
- Foam seal on the heater core for the heater. Refer to HEATER CORE, REMOVING AND INSTALLING .
-- Set the highest possible temperature.
- Turn the temperature regulator -1- to the "warm" stop.
-- Measure the temperature of the air coming out of the left and right instrument panel vents with a thermometer.
Target values with an engine temperature of about 90 °C (194 °F):
- The temperature of the air from the instrument panel vents goes above 55 °C (131 °F).
- The temperature deviation between the left and right side is less than 8 °C (46.4 °F).
if The Target Values Are Not Reached, Check The Following:
- Coolant circuit bleeding. Refer to COOLANT CIRCUIT FILLING AND BLEEDING [CRUA, DEJA] / COOLANT, FILLING (BLEEDING) [CNSB, CNTC] .
- Incorporation of the heater core for the heater into coolant circuit. Refer to COOLING SYSTEM/COOLANT [CRUA, DEJA] / COOLANT SYSTEM/COOLANT [CNSB, CNTC] (Connection Diagram for Coolant Hoses).
- Foam seal on the heater core for the heater. Refer to HEATER CORE, REMOVING AND INSTALLING .
- Actuation and function of the Temperature Regulator Door Motor -V68- using the :Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
- Function of the temperature door in the heater. Refer to OVERVIEW - AIR DISTRIBUTION HOUSING DOORS AND PARTITIONS .
- Engine Coolant Thermostat. The engine coolant may not heat properly if the coolant thermostat is faulty. Refer to COOLANT PUMP/COOLANT THERMOSTAT [CNSB, CNTC] / COOLANT PUMP/THERMOSTAT [CRUA, DEJA] / COOLANT THERMOSTAT, CHECKING [CRUA, DEJA] (Coolant Thermostat, Checking) or use the Vehicle Diagnostic Tester (depending on the engine).
- Engine coolant pump. Refer to COOLANT PUMP/COOLANT THERMOSTAT [CNSB, CNTC] / COOLANT PUMP/THERMOSTAT [CRUA, DEJA] (Coolant Pump Overview).
- If installed: Check the After-Run Coolant Pump -V51- / Heater Support Pump -V488- (different designations, depending on the engine) and the Coolant Shut-Off Valve -N82- function. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
For vehicles with an After-Run Coolant Pump -V51- / Heater Support Pump -V488- (different designations, depending on the engine), bring the engine RPM to approximately 2000 RPM and repeat the test if necessary. If the air temperature goes above 55 °C (131 °F) when repeating the test at a higher engine speed, this indicates that there is too little coolant flowing through the heater core for the heater. Cause: The delivery rate of the engine coolant pump is too low while idling or the incorporation of the heater core for the heater into the coolant circuit is not according to the specification. Refer to COOLING SYSTEM/COOLANT [CRUA, DEJA] / COOLANT SYSTEM/COOLANT [CNSB, CNTC] (Connection Diagram for Coolant Hoses).
If too little warmed up coolant flows through the heater core for the heater, the required heat output is not reached.
-- Set the lowest possible temperature.
- Turn the temperature regulator -1- to the "cold" stop.
-- Measure the temperature of the air coming out of the left and right instrument panel vents with a thermometer.
Specified Values:
- After five minutes the measured values must be a maximum of 15 °C (59 °F) greater than the measured ambient temperature.
- The temperature deviation between the left and right side is less than 8 °C (46.4 °F).
if The Target Values Are Not Reached, Check The Following:
- Actuation and function of the Temperature Regulator Door Motor -V68- using the :Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
- Function of the temperature door in the heater. Refer to OVERVIEW - AIR DISTRIBUTION HOUSING DOORS AND PARTITIONS .
- Foam seal on the heater core for the heater. Refer to HEATER CORE, REMOVING AND INSTALLING .
- Measured value for the Evaporator Vent Temperature Sensor -G263- using the :Vehicle Diagnostic Tester in the"Guided Fault Finding" function.