Help... "Increased Emissions" fault code

[SilverSlug]

My check engine light came on, "Increased Emissions."

I've searched and read several different reasons for this... O2 sensors, secondary air pump valves, thermostat, fuel tank breather sensor, and/or old battery.

Is there a way to truly diagnose it without spending time/money on all of those things hoping one will work?

[RE36TRO]

Have to pull the code plain and simple. It can be a variety of things. I was in the same boat, can't act without diagnosing first.

[SilverSlug]

Originally Posted by RE36TRO

Have to pull the code plain and simple. It can be a variety of things. I was in the same boat, can't act without diagnosing first.

Indeed, I wrote down the codes before I cleared them, but now can't find the little receipt I used

I'll pull them again if/when it comes back.

Did you have an Increased Emissions issue as well?

[dty3]

Silverslug
i had the same issue, here was my fix
https://www.m3post.com/forums/showthread.php?t=1359834

[SilverSlug]

Originally Posted by dty3

Silverslug
i had the same issue, here was my fix
https://www.m3post.com/forums/showthread.php?t=1359834

Wow thanks!

So after you cleaned out the connector to the fuel pump pressure sensor... it has still been all good since back then??

[Gossypiboma]

Originally Posted by SilverSlug

Wow thanks!

So after you cleaned out the connector to the fuel pump pressure sensor... it has still been all good since back then??

The error Increased Emissions can mean 100 different things, it is a generic term. Have the codes pulled to find out whats the issue.

[dty3]

i bought a replacement part, it was not to expensive and reconnected everything

[SilverSlug]

Ok, after clearing the code... Increased Emissions has returned.

The code is P0128. Does it mean it's the thermostat after all?

[Sh0ty]

Generally speaking, yes. The other possible root cause is failure of a coolant temperature sensor. In-range failures of sensors are relatively uncommon, so it’s a good bet that it’s the thermostat (or a poorly calibrated coolant temperature model, but I doubt it).

The way most coolant temperature sensor rationality diagnostics work is by comparing the measured coolant temperature against a modeled temperature. The model assumes correct function of the thermostat, so if your thermostat is stuck open, then the measured coolant temperature would be too low when compared to the model.

[SilverSlug]

Ahh okay thanks. So while I'm in there, I should probably replace the coolant sensor and water pump, ya?

I'm at 92k, so this should help assure I don't have to get back into that way for any foreseeable future?

[Adriano917]

Thats a bad thermostat for sure, its an easy fix. Make sure you buy the O-rings to back pipes and when you install them make sure you don’t pinch them! Not a bad idea to replace the water pump but you do need to remove more things.

[SilverSlug]

I'm just on the fence about doing the water pump since it's not broken, and there doesn't seem to be many cases of them failing, nor even leaking... Is there?

Also, the Rein water pump seems to have the best reviews, and is only $104, but is on back order at ECS with "no ETA", which further makes me think I should just do the thermostat and possible coolant sensor, and call it a day.

Do these water pumps start failing or leaking at a typical age/mileage?

[SilverSlug]

Also, which O-rings are you talking about?

The water pump comes with the sealing o-ring, are there additional ones?

[Sh0ty]

So while I'm in there, I should probably replace the coolant sensor and water pump, ya?

Personally, I would not replace the sensor. The probability that it's stuck in-range is extremely low. There is also the (small) risk that you get a bad replacement sensor. Water pump is probably not a bad idea though.