Checking heat output and actuation of temperature flaps on vehicles not fitted with an air conditioner — AUDI

🧭 Before you start

Fits: Audi A4 B9 (8W, 2015–)

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• On vehicles with a start/stop system, the engine may only run if additional heat output is required to attain the set temperature.

📋 Procedure

1. Close the front lid, doors, windows and sun roof.
2. Open all dash panel vents.
3. Start the engine and make the following settings on the heater operating and display unit E87(A): [Note: On vehicles with a start/stop system, the engine may only run if additional heat output is required to attain the set temperature.] [Note: Vehicles with an engine with regulated coolant circuit (e.g. with a regulated coolant pump and coolant valve for cylinder head N489) are currently not fitted with N82. On engines with a regulated coolant pump, the engine control unit actuates the coolant pump to regulate coolant circulation 19Cooling system/coolant; Connection diagram - coolant hoses.]
4. Measure the ambient temperature.
5. Start heater guided fault-finding and select the "“Reading measured values”" function .

6. Run the heater for several minutes in this setting (fresh air mode, "“Cold”" temperature setting, fresh air blower V2 set to maximum speed). [Note: On vehicles with no air conditioner, the evaporator output temperature sender G263 is used to determine the temperature of the fresh air drawn in (no built-in evaporator operation).As the air flow is routed to the front left chest vent temperature sensor G385 in this setting, use is not to be made of the measured value of the left footwell vent temperature sender G261 (if necessary, alter the air distribution setting accordingly at E87).G385 is installed in the air duct to the "“Centre”" dash panel vents. To determine the temperature of the air from the left and right dash panel vents, it is appropriate to measure the temperature at these vents with thermometers.]
7. Compare the measured value of G263 to the measured values of G385 (and G261).
8. Set the highest possible temperature on E87.
9. Read off the measured value of G385 (and G261).
10. Use a thermometer to measure the temperature of the air emerging from the left and right dash panel vents. [Note: On vehicles with no V50/V55 (different designations depending on engine), set the engine speed to roughly 2000 rpm and repeat the test if necessary. If the temperature of the air increases above 55°C on repeating the test at increased engine speed, this is an indication that not enough coolant is flowing through the heating system heat exchanger. Cause: Inadequate engine coolant pump delivery at idle or heating system heat exchanger not incorporated into the coolant circuit in the specified manner Engine, mechanics19Cooling system/coolant (connection diagram for coolant hoses).The required heat output is not attained if insufficient heated coolant flows through the heating system heat exchanger.]
11. Set the lowest possible temperature on E87.
12. Read off the measured value of G385, G263 (and G261).
13. Use a thermometer to measure the temperature of the air emerging from the left and right dash panel vents.

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