I have noticed, particularly in the winter, that my temperature gauge is about 5 degrees too warm. I do understand that road surfaces can have an impact on the temperature reported - but even on a non heated road it is too high. I read somewhere that you can calibrate the thermometer - does anyone know how to do this?

Tim

 

I'd ask your service dept about checking it; I don't know of any user-adjustable method, since we have no input to the OBD system.

I think the display is taken from the OBD inlet air temp sensor, which is not necessarily equal to the outside air temp- the air has already swirled around in proximity to the engine a little. With a larger temp difference in winter providing a more rapid temp change, the reading will be "more wrong" in winter than summer.

 

Nope - it's a little different than that. There's an external sensor behind the bumper cover on the LH (driver's) side. You adjust the calibration via the trip odo reset button, IIRC.

The procedure is in the owner's manual. I don't have that in front of me right now, but it's there. I'd suggest getting a reference source to compare before adjusting it.

BTW - I see they've now removed the 'download owner's manual' option from OwnerLink (gee, do they get a kickback from Helm ?) , so you'll have to refer to your printed copy.

An interesting (?) aside - For DX / LX's that didn't get the sensor, it's available as a dealer-added option, but for those cars where it's added after the factory, the car can't also have OEM fog lights installed (although EX owners can get fogs, having had the sensor factory-installed).

 

Actually I can answer my own question. From the manual:

You are able to adjust the outside temperature display plus or minus 5 degrees. Hold the select/reset **** for 10 seconds. The following sequences appear, 1 second at a time: 0,1,2,3,4,5,-5,-4,-3,-2,-1,0, 1 (0,1,2,3,-3,-2,-1,0,1)
When the temperature reaches the desired value, release the select/reset ****. You should see the new temperature displayed.

 

There are a number of ways to calibrate a digital thermometer. You will have to find out where the sensor is located and what type of sensor it is, (thermocouple or electronic). It may be somewhere near the engine compartment where it could be getting warmed slightly by the engine. Or, it could be mounted high up on the roof molding somewhere.

The best way to calibrate a digital thermometer is with an "ice point" cell. Immerse the sensor in some ice water then find out where the adjustment/calibration potentiometer is and adjust accordingly to 32F or 0C. I wouldn't mess with the high end, 212F, 100C as you could get burned.

 

the ol' RTFM rears its head again...on me...