Heating issue

[Asac]

2018 PHEV. No heat after battery 12v swap. Correct battery OEM. 400 plus USD. Second dealership. Mitsubishi. Also clean filter, flush, new 12 volt aux pump, new 4 way valve. Vehicle is in air-con mode . 160. Bucks an hour for unfamiliar techs crawling around vehicle. Now they have to contact a platform engineer in Japan to help them. Will keep posted. Car is in Akron Ohio.

 

[Asac]

Tech has been in contact with platform engineer. Mitsubishi themselves are stumped. Will give an update. Now they are leaning towards a heater matrix issue. They say they are chasing air bubbles. Obviously, they have 50 plus coolant lines going everywhere from bumper to bumper.

 

[Stu37]

Try setting max air conditioning for a few minutes and then maximum heat.
The heating now works perfectly

 

[Phev2016]

Ask them to remove the filter near the 4 way valve and confirm it has no build up of 'gel' which would stop/slow flow. There are many threads explaining this common cause (search filter heating) and there is a known method to flush out the system - citric acid I believe. Also, there might be many coolant lines but most mechanics seem able to bleed the system, even if it takes a few attempts and your mechanics should be able to check the heater matrix by flushing it with a hose. Coincidentally there is a thread that was updated today "2019 2.4 heater fail" which has a link to this very good video that explains a lot - this one already had the filter cleaned and they checked the matrix was ok too but they haven't yet fixed it!.

2019 2.4 heater fail​

 

[Asac]

I have exact same symptoms. It has a new 4 way and aux pump.

 

[Asac]

Try setting max air conditioning for a few minutes and then maximum heat.
The heating now works perfectly

What was the problem with the vehicle ?

 

[Phev2016]

Ask them to remove the filter near the 4 way valve and confirm it has no build up of 'gel' which would stop/slow flow. There are many threads explaining this common cause (search filter heating) and there is a known method to flush out the system - citric acid I believe. Also, there might be many coolant lines but most mechanics seem able to bleed the system, even if it takes a few attempts and your mechanics should be able to check the heater matrix by flushing it with a hose. Coincidentally there is a thread that was updated today "2019 2.4 heater fail" which has a link to this very good video that explains a lot - this one already had the filter cleaned and they checked the matrix was ok too but they haven't yet fixed it!.

2019 2.4 heater fail​

Update, they now have 4 videos and fixed it by flushing the system with oxalic acid which is what dealers are supposed to use. They found gel and aluminium particles in the system which has been said in other threads on this forum