I own a 2006 Mazda 5 - about 75k miles. Check engine light came on a couple months back on a drive over the pass. I got the code checked once we got down the other side and got:

P0126 Insufficient Coolant Temperature for Stable Operation

Since that trip, the light will stay on for several days, then just be off one day when I come out to drive to work. It usually stays off then until I take a longer drive at higher speeds. Then this pattern repeats.

I tried the standard-operating-procedure: upping my coolant, and making sure the gas cap was secure. No fix.

This appears to have something to do with the thermostat getting stuck open.
via: PO126 Insufficient Coolant Temperature error code - MX-5 Miata Forum

I am planning to replace it soon here. Anyone else have experience with this? Suggestions?

Many thanks!

-Adc

 

...and...this should be in the Mazda 5 area.

Facepalm. Sorry, it's early here and I'm still half awake.

 

....or....in General Tech.

maybe there is an air bubble in the cooling system that makes itself known when the temps rise. Or the water pump is in marginal shape.

It is old enough, replace the thermostat and get the cooling system flushed. See what happens. Anyway that is what I would do.

 

Time to change the coolant and change the thermostat (agree with TanProtege).
If that doesn't fix the problem, then change the coolant temp sensor.
Quit driving like a Old Fart (just teasing).
Pressing the gas pedal down further will warm the engine up quicker!
Good Luck!

 

got a 2006 mazda 5 and started doing the same thing Nov '11 with about 75k miles on the car. I reset the light and a week later it comes back up. I know another guy at work with a 2006 mazda 5 and it started doing the same at 65k. He changed the coolant and thermostat and fixed it... I will try the same thing. let you know if it works.

 

wow - this thread is really interesting because I just got this code yesterday and I have a 2006 Mazda3 that just hit 80,000 miles. Anyone try any of the suggestions on this thread and have it work or not work? I'd be really interested in hearing how things turned out for you guys. Thanks!

 

I'm experiencing the same thing. I've seen the most common posts suggested it is a sticky thermostat. My question is, are there long term implications if I don't fix it immediately? I'd like to try to fix it myself, but without a warm garage I don't want to get under the car in the middle of winter. If anyone has gotten the fix professionally, how much were you charged?

 

Long term implication would be a cooked engine and a big repair bill.

 

As far as cooking the engine, my experience, as well at that of other posters I have seen is that the temp gauge never leaves normal operating temp range. I would think that the gauge is linked to the thermostat, but when the check engine light comes on with the code, the needle doesn't move. Are there two separate temp sensors, and if so which would be more accurate, the dash gauge or whatever is setting off the check engine light?

 

Most Mazda's have a normal operating temp range of 70 - 110 degrees centigrade.

Im not sure how hot it needs to be to reach 3/4 on the guage or higher.

Some cars use more than 1 sensor, others relay the reading into the PCM then onto the instrument cluster.