temp and fuel gauge calibration

[Tom Trueb]

I have seen both these mentioned in past posts, but would like to know if others have the same perception and any known corrections. I have a 2010 Mazda 5 Sport auto.
#1: Low fuel light comes on with 3.5 gallons left in tank with six o'clock gauge reading shortly after; this is over 94 miles to empty! Dealer says it is a good thing, cannot be corrected with software, would have to replace sender unit (dropping tank) if it's that big a deal to me. Well, to me, it's like crying 'wolf', and I would rather delay worrying until a more realistic level instead of driving almost 100 miles on 'empty'. Why even have a fuel gauge if I have to go by a trip odometer to get reliable information?
#2: Ambient temp gauge consistently reads 4 degrees too cold. Have not discussed this yet with dealer, but would like for it to be correct. Although this sensor would be a lot easier to replace, can it be calibrated with software?
I asked the dealer if either of these concerns had been reported, but haven't heard back yet. With all the computerized stuff on modern autos, I can't help but ask if something's being overlooked here. Thanks for any input.

 

[flcruising]

The gauge could be 'fixed' 1 of two ways yourself, but it would make the FULL level be lower than you're used to.
1) Pull the needle and rotate it clockwise until you're happy with the position.
2) Add a resistor to the signal wire of the sending unit. You'd have to determine the proper resistance based on your own measurements.

Ambient temp sensor could also be 'fixed' with option (2) above.

 

[Tom Trueb]

Aaron, thanks for information. Changing impedence in signal wires is why I asked about software calibration. Since this is a new vehicle, I'm going to ask the dealer fix under warrenty. I don't like nit-picking, but these errors do seem excessive for a new car. Tom

 

[thaxman]

Well, to me, it's like crying 'wolf', and I would rather delay worrying until a more realistic level instead of driving almost 100 miles on 'empty'. Why even have a fuel gauge if I have to go by a trip odometer to get reliable information?

Mazda probably did this to prevent people from driving all the way to empty & pulling all sorts of impurities through the fuel lines, blowing out or clogging up the fuel filter and possibly affecting the injectors. When I get the light, I know I will be filling it in 45-60 miles MAX.

 

[Martyd]

I have always felt that the ambient temperature readings in my 2010 Sport are not accurate. I go through long periods of no change, even though I know there is a 5 or more degree change since I got in the car. Don't know if the sensor is bad, or the electronics fail to update. Do I want to have the dealer pull it all apart for the fix? That's my dilemma.

 

[IAATM]

I have a 2013 Sport, and the non-linearity of the fuel gauge is really outrageous. Over the weekend, after filling up, I drove for ~150 miles before the first little square of the fuel gauge bars went dark. Much later on, but still on the highway, I had a 1/4 tank remaining (3 little squares) when I noticed the total mileage on the trip odometer indicated that at ~30 mpg, I should probably be getting close to empty. As I was driving, thinking about the theoretical mileage, glancing periodically down at the guage, and calculating how there could still be 3-4 gallons in the tank, all three bars suddenly went dark, and the empty-fuel warning light came on!

I'm still under warranty, so I'm going to take it back to the dealer and ask him to fix it (replace the sender, circuitry, etc). Before I do so, have any of you experienced the same non-linearity in your gauge, and if so, how did you remedy the situation? Are there any TSB's circulating out there about faulty senders or circuitry?

 

[90210]

Before I do so, have any of you experienced the same non-linearity in your gauge, and if so, how did you remedy the situation? Are there any TSB's circulating out there about faulty senders or circuitry?

After owning 9 mazdas, I learn to live with it. 2012+ 5 doesn't even have a temp guage.

See if your dealer will "fix" that too

Good luck. Let us know how you come out

 

[Davicho]

My ambient temp readout constantly reads about 5-10 degrees cooler then it really is. It bugs the s*** out of me. I want to replace the sensor but at ~$55 it's not a cheap trial and error. Does anyone know for sure if replacing the sensor will fix this issue? Or does anyone know how to reset the read out?

 

[90210]

^^^
Interesting.

My outside temp sensor reads 1-2 degrees of my phone only. Its the onyl acurate thing on my MZ5!