STOP / START NOT WORKING, WHY!?

STOP/START is a feature on modern cars to reduce emissions by reducing the idle time on your engine when stationary. This works in theory but in reality, there are often issues causing this system to not work as intended.
there are certain criteria that needs to be met inorder for the system to work properly.
this differs from manufacturer to manufacturer so we always recommend checking out the owners manual for a comprehensive list, but we will go through the main reasons that people run into issues here.
1. AC, Your Air conditioning being active is considered too high a draw on the battery when the engine isnt running. the car recognises this and to prevent not having enough power to restart, it de activates the function all together.
2.Engine coolant temp. the biggest reason for wear on your engine is during a cold start up. this is because the oil hasn't been fed through the engine yet so the car intentionally waits until the coolant temperature is above a certain limit which ensures a good operating temp for the engine and that sufficient oil has gone through the internals of the engine. once this criteria is met, stop starts when warm have minimal wear effect.
3. Repeated stop starts. once a succesful stop and start has been carried out by the system, there is a minimum distance and/or speed that has to be met before another stop start can occur. this is to again ensure the engine has enough time to recirculate oil through the engine and prevent premature wear.
4.DPF clean. the diesel particulate filter collects soot from the engine and occasionally runs through a self clean procedure. while this procedure is being carried out the engine must remain running. if it is interrupted then the process will need to be repeated the next time the car is started up. the system knows this and de activates the stop start system to make sure it doesn't interrupt the procedure. too many failed dpf cleans can cause a blockage in the dpf.
5. Battery State of charge. the battery must be over 80% charged. if this threshold isnt met, then the stop start wont work. This is because the system weighs the risk on if there is enough charge to restart the engine similar to the AC issue.
if however the engine stops but you are waiting for a prolonged period of time, the battery may fall bellow the 80%. this would mean the auto start up kicks in before intended as a way to counter act the issue. this auto start up would kick in if any of the listed criteria isnt met.

Stop start complaints will be very common the more people start using their cars again after lockdown. we hope this video has given you something to think about if you run into these issues.

hope this helped, have a great day and STAY SAFE people!

Видео STOP / START NOT WORKING, WHY!? канала MTM Motor Services