Instruments - Incorrect Outside Ambient Temperature Display
90 Outside air temperature reading: General Information
90 12 38
2032113/1
December 7, 2012.
Affected Vehicles
Condition
The customer may state that the outside ambient temperature display is incorrect.
Technical Background
To achieve a smoothening effect of the displayed outside ambient temperature, the value shown does not instantaneously follow the temperature
sensor measurement. The display will not change faster than 4锟斤拷F (2锟斤拷C) per minute. This concept applies to both falling and rising temperatures.
A programming strategy is also implemented to avoid incorrect readings on a parked vehicle, due to the temperature sensor being affected by outside
influences such as radiant heat from the engine bay, elevated road surface temperatures, etc. Incorrect readings are avoided through the following
logic:
^ After switching the ignition on, temperature changes are only shown after 30 seconds for a stationary vehicle (vehicle speed = zero and engine
switched off).
^ Only when the vehicle drives faster than 12 mph (20 km/h), rising temperature values are displayed during the first 3 miles (5 km).
^ If the measured ambient temperature is above the displayed value, but falling, the display is not changed.
^ When the coolant temperature reaches 104锟斤拷F (40锟斤拷C) and the speed drops to under 12 mph (20 km/h), only falling ambient temperature values
are shown. For example, in stop and go traffic when the vehicle is often below 12 mph (20 km/h), it can take some time before the displayed
temperature is correct.
^ If conditions above are noted during these typical driving scenarios, the sensor is not at fault and does not need to be replaced.
Production Solution
Not Applicable
Service
Explain the operation to the customer.
Warranty
This TSB is informational only and not applicable to any Audi warranty.
Additional Information
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service
manuals for the latest information.
