Instruments - Ambient Temperature Display Inaccurate

Bulletin no: 09-015/11

Last Issued: 06/13/2011

Subject:
DISPLAY SHOWS INACCURATE AMBIENT TEMPERATURE





APPLICABLE MODEL(S)/VINS

DESCRIPTION

Some customers may complain that the ambient temperature display is not accurate, or it takes too long for the display to show actual temperature.





When you encounter a customer with this concern, first verify the condition when the customer noticed this symptom. If the condition is similar to the following CONTROL LOGIC OF AMBIENT TEMPERATURE" or DIFFERENCE BETWEEN THE TEMPERATURE DISPLAY AND OTHERS", advise the customer that this is a normal characteristic of the vehicle and not a malfunction.

If the condition does not meet the following and the sensor malfunction is suspected, make sure to inspect the sensor according to M53 online or Workshop Manual (section 09-22 AMBIENT TEMPERATURE SENSOR INSPECTION).

Replace the sensor only when it fails the Workshop Manual inspection.

CONTROL LOGIC OF AMBIENT TEMPERATURE

^ The ambient temperature display is NOT always equal to the reading of the temperature sensor mounted in front of the vehicle.

^ Under certain conditions, the sensor reading is adjusted in order to avoid false high reading due to heat from engine and/or road surface.

^ The ambient temperature display is adjusted during the following conditions shown below.

^ Due to this adjustment, the temperature on the display may temporarily differ from actual.





EXAMPLE OF CONDITIONS WHEN SENSOR READING IS ADJUSTED

NOTE:
^ When M-MDS is connected, the ambient temperature shown on M-MDS is the actual temperature sensor value; however, in some cases, it may not match the instrument cluster display because the value may be adjusted. Do NOT attempt repair due to this difference.

^ If temperature sensor connector is disconnected then connected, the recorded temperature is lost and the display starts to show actual sensor reading regardless of the condition. Sometimes it is misjudged that the symptom is fixed by the sensor replacement, but actually, the display has reset and now shows actual sensor reading because the connector was disconnected. So the sensor is not the root cause.

DIFFERENCE BETWEEN THE TEMPERATURE DISPLAY AND OTHERS

If the vehicle's temperature display does not match an external temperature display (such as a bank sign showing outside temperature), this is because the external temperature display does not always show the temperature around the vehicle.