Heating Output And Temperature Control Door Activation, Checking, Vehicles Without A/C System
HEAT OUTPUT TEST INFORMATION AND TOOLS REQUIRED
Test Requirements
- Coolant circuit bled according to specifications. Refer to [FOR ENGINE(S) DLRA, DJJA] COOLANT SYSTEM/COOLANT .
- All air ducts, covers and seals are OK and properly installed.
- Seal between engine compartment, hood and plenum chamber is OK and installed correctly. Refer to BULKHEAD ; (Overview - Plenum Chamber Cover) to check.
- If installed: After-Run Coolant Pump -V51- and the Coolant Shut-Off Valve -N82- function is OK.
- The airflow through the dust and pollen filter is not obstructed by debris. Refer to DUST AND POLLEN FILTER, REMOVING AND INSTALLING to check.
- The air intake for the heater (in fresh air and recirculating air mode) is not obstructed by debris 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 using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
- The coding and adaptation of the Heater Control Module -J65- control head was checked using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
- Vehicles with 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: the actuation and function of the parking heater is OK. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
Checking
-- Close the hood, doors, windows and sliding 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 setting regulator -21- to the "cold" stop.
- Set the air distribution regulator -4- to "instrument panel vent".
- Turn the fresh air blower regulator -16- 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.
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 specified values are not reached, check the following:
- Check the seal between the engine compartment, hood and plenum chamber and repair if necessary. Refer to BULKHEAD ; (Overview - Plenum Chamber Cover).
- Repeat the test while measuring the temperature of the air drawn in via the fresh air intake for the heater in the plenum chamber with one of the two temperature sensors with the hood closed. The permissible increase of air temperature in the heater (between the air intake 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 Control Door Motor -V68- using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
- Function of the temperature control door in the heater. Refer to AIR DISTRIBUTION HOUSING, REMOVING AND INSTALLING .
- Foam seal on the heater core for the heater. Refer to HEATER CORE, REMOVING AND INSTALLING .
-- Set the highest possible temperature.
- Turn the temperature setting regulator -21- to the "warm" stop.
-- Measure the temperature of the air coming out of the left and right instrument panel vents with a thermometer.
Specified values with an engine temperature of approximately 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 specified values are not reached, check the following:
- Coolant circuit bleeding. Refer to [FOR ENGINE(S) DLRA, DJJA] COOLANT SYSTEM/COOLANT .
- Incorporation of the heater core for the heater into coolant circuit. Refer to CONNECTION DIAGRAM - COOLANT HOSES (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 Control Door Motor -V68- using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
- Function of the temperature control door in the heater. Refer to AIR DISTRIBUTION HOUSING, REMOVING AND INSTALLING .
- Engine coolant thermostat. The engine coolant may not heat properly if the coolant thermostat is faulty. Refer to [FOR ENGINE(S) DLRA, DJJA] COOLANT PUMP/THERMOSTAT (Coolant Thermostat, Checking).
- Engine coolant pump. Refer to [FOR ENGINE(S) DLRA, DJJA] COOLANT PUMP/THERMOSTAT (Overview - Coolant Pump).
- If installed: check the function of the After-Run Coolant Pump -V51- and the Coolant Shut-Off Valve -N82- using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
For vehicles without an After-Run Coolant Pump -V51-, set the engine speed 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 CONNECTION DIAGRAM - COOLANT HOSES (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 setting regulator -21- 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 specified values are not reached, check the following:
- Actuation and function of the Temperature Control Door Motor -V68- using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
- Function of the temperature control door in the heater. Refer to AIR DISTRIBUTION HOUSING, REMOVING AND INSTALLING .
- Foam seal on the heater core for the heater. Refer to HEATER CORE, REMOVING AND INSTALLING .
- Measured value for the Evaporator Temperature Sensor -G308- using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.