Hi guys, this issue has had me stumped for a few weeks already. Hoping to get some insights or to see if anyone else has the same experience

Driving a 2019 Proton Iriz (Premium).

The past few weeks I've been smelling this very odd smell in the cabin of my car, I can't describe it but it's slightly kinda "choking" or "sticks to the throat" (words from an aircon specialist).


So went through some troubleshooting and I've narrowed it down to the following:

When it happens:
Idling in traffic, i.e. car stopped by traffic light OR in standstill traffic jam with other cars (front and/or side, doesn't matter). The smell takes a few minutes to start; once it gets in, it'll go away after I continue driving. It never happens during driving, even if slowly in moving traffic jam.

Some troubleshooting I've done myself and with Proton SC (twice already) and an aircon specialist:
1) Sometimes idling with no traffic around also has the smell, but rarely (when in porch, in carpark with no cars around or cars without engine on)
2) Proton SC jacked up my car and checked the exhaust from under, no cracks and no leaks, no smell even when face up close to the exhaust; as usual SC said got some smell is normal but this smell is definitely not normal
3) Changed cabin filter to new one, to no avail
4) Aircon specialist checked the recirculation valve/foam-thing and everything working fine and seems to seal properly
5) Aircon specialist said it smells like cooling coil smell and checked the coil; it's not mouldy or dirty. He blasted it with air to also sorta ventilate it a little bit, but the smell has still returned in the scenario above.
6) When the smell starts, I put my face directly at the aircon but I don't really smell it coming from the air.

I'm really frustrated and confused, I have no idea what could be causing this issue. Is this an aircon system thing or something else entirely? The aircon specialist is saying that he may need to disassemble the entire dash to check everything thoroughly (RM900+ inclusive of cooling coil replacement, is this price ok?)

Can anyone share if there's any similar experiences or an idea of what this could be?

To eliminate if this is really a aircon issue, have you tried leaving the aircon off in d jam to see if this happens? You can switch off the aircon but leave the blower on to have some air movement.

Also in my opinion, if the smell only happens when the car is stationary, very likely there is an opening to the cabin that it open e.g. ventilation vent in d boot, a seal/rubber grommet in the firewall that is leaking, or boot/door rubber weather strip.

same happened to me once, couldnt find the reason. just sold the car

Thanks for sharing! Good point, I'll give it a try in jam tonight with blower on and aircon off. If the smell doesn't happen, then this would suggest that it's a purely internal system issue and not air from outside right?

The aircon specialist did take a look see at the firewall and everything seems intact, but he just eyeballed it without any testing. Need to check the boot ventilation, never really looked at it


What year Iriz was this? Can share a little on what/how you checked?

lucky mine doesn't do this, sometimes only when going through really smelly place such as next to palm oil refinery and etc.

have to try to switch it to blower only(press the temp button) when the smell is there? have you try to switched off inside air circulation to let air outside to enter? will all of them produce same kind of smell?

perhap is plastic melt, airbag gas or something else inside dashboard.
not aircond,

btw rm900 very costly. may diy learn to open urself, since this is msia made car. we can do it

Does it smell like plastic burning? Because you said "choking" or "sticks to the throat"...

Thank you so much for the recommendations!

So I tested today, whole morning in traffic just trying with blower on + AC off... lo and behold, the smell is not there. I also tried turning the AC on after a while in traffic jam and the smell came back after a minute or two, then it lingers a while after I turn off the AC. Seems like it's an AC issue --could it be the cooling coil?

Not exactly, but I'd say it's thereabouts plastic / chemical smell

That RM900 is to disassemble the whole dashboard and replace the cooling coil, that's not something I'd be comfortable doing

I’m not an expert but I’d be worried whether something behind the firewall is coming into close contact with the engine and during idling, there’s reduced heat dissipation and hence the smell enters the cabin. Might need to expand the search to beyond the air conditioning system….

Good luck my friend!

yea wire burning insulation skin is slight different than normal plastik

Maybe aircond cooling coil clogged by heavy dust. Buy aircond cleaner spray from mr diy rm13.95. Remove glovebox, cabin filter then spray into the blower. Then start engine, off aircond, put fan level 4 drive around 2~3km. Dirty water will discharge from the aircond hose. Even problem not solves, atleast rm13.95 aircond spray lemon smell will relieves the smell problem.

so bro, do you solved it already?

2018 Myvi here. Had an issue where the AC blew burnt chemical kind of smell. Got the whole thing serviced for RM700. The coil is dirty and leaking. Have to leave it for half a day at workshop where they dissemble the dash and did all the cleaning and such in it.

Usually if rotten smell due to lizard dead body inside AC system

RM700 just to get it cleaned? I would rather pay more to replace the coil.

Yes replaced the coil obviously.

Spoken to 2 Proton SCs and 1 aircon specialist already, seems very unlikely for this to be the case, because it only happens in very specific scenarios as per my first post

Unfortunately, it's only when I'm in traffic, so seems quite unlikely. First time I brought to SC they cleaned out the blower for me tho.


Unfortunately not yet But seems like no matter what, need to get the dash diassembled for the cooling coil replacement. Costs RM850 for one day work at an aircon specialist, seems okay lah.




Thanks for sharing! Was it a constant smell or only during specific scenarios like mine (i.e. stuck in traffic)?

becos u know. our nose is less sensitive during cold.
umpama loss of taste.

Sharing more updates on this anxiety-inducing thing:

Took to another aircon specialist to double check, he didn't try to smell it but based on my explanation he sealed up my external recirculation and plugged a potential leak in the cooling coil hose entry from the engine bay. Basically troubleshoot external smells and seems like external smells wasn't the issue after all.

Tested it again in traffic today and to no avail, the smell is still present... So I tried again in 3 different scenarios:

1) In traffic light traffic (idling + motion), aircon off, blower on: Smell is there somehow, previously it wasn't (as per my first post)

2) In traffic light traffic (idling + motion), aircon off, blower off: Smell is still there somehow

3) Idling in empty road (no traffic whatsoever, idling few minutes then drive off), aircon off, blower off: Smell is there


IDK if my mind is playing tricks now, but with the aircon and blower off, the smell seems to eminate from the centre console, the smell is not so obvious in the driver's seat without the blower/aircon on

At this point, I'm not even sure if it's an aircond issue. Could this be a handbrake or brake thing? Or... CVT clutch burning up? Since idling and motion


This is driving me crazy

This post has been edited by Helldiver: Nov 21 2023, 08:41 PM

So... I solved the problem


The whole issue is nothing to do with exhaust or aircon, but related to burning plastic and wire.

The third-brake light was burning up, the housing has a big chunk melted off. Which explains why the burning smell only happens when idle and accelerate (foot on brake)

This issue is truly bodoh tahap gaban.

To anyone having weird smells in their cabin next time, do check the brakelights as well


Case closed, thank you everyone for their contribution