Hi I have a 2015 mazda cx5. I have noticed that the accelerated warm up system has been intermittent since I brought the car in September but I understand it is all related to temperature of certain components. However the last few days with the change in temperature and the cold weather I would imagine that these would be the prime time that the AWS would kick in. Yet the past week it hasn't happen at all. Yet this morning for instant is the coldest morning we have had so far with the car only reading 5 degree. In turn I have noticed my fuel consumption has also been awful this past few days. My drive to and from work is 5 miles yet my fuel consumption has been dropping like 15 to 20 miles on these trips something that it isn't usually like. Could I have a fault with the AWS??? I did have a recall on the car where I had to have the soft ware up dated ciuld thishave had an affect?

 

When you say its intermittent, what's happening? is it idling too high? too low? Stalling?

A 5 minute drive will not fully warm up the engine, continual short trips like this is not good for the engines health & economy.

 

 

Mileage? Get the dealer inspect the throttle body, might be dirty.

 

Hello Matty, I have the exact same issue. I have a 2014 Mazda CX5, 2.2 diesel, and the accelerated warm up system does not always work. Initially I thought that this was somehow normal, but for the past few months, I noticed that the auto warm up system rarely kicks in, maybe 1 out of 10 start ups. It is also absent during the cold days which is not normal at all. I bought my car second hand, and first thing I did when I took the car, I had the local Mazda dealership update my ECU, concerned with the DPF issues.
I believe this is an electronic/ECU issue and not a mechanical fault. I tried to search online for others with the same issue but is hard to find a definitive answer to the problem. Although it is annoying, it is not the end of the world. I always wait for a few seconds for the oil to circulate and warm up before start driving my car. I am not a big fan of dealerships, therefore I will not go back to them for this issue.