Check engine light and Econ light not coming on

[miles01]

The check engine light all of a sudden came on and the ecno light is not coming on as well as MDS is not working today. The truck still drives normal with no miss and performance is as good as it always was, with the same mileage according to the evic.
I can tell when the MDS was working on my truck because I can hear it and feel the vibrations as well as the difference in power. It does transition into and out of the MDS very smoothly and quietly but I do notice the difference. The only time it worked before was in city driving with very light peddle or on the height going 100kmh or less on very flat or down hill and no head wind.
Truck is a 2018, 2500 with 3.73 gears, 6 speed transmission, crew cab Laramie, with rambox.
Does anyone know what the problem might be.

 

[olyelr]

Just go get the code scanned and it will tell you.

I find it funny, though...my half ton is throwing a code for a failed fuel sensor (damn red squirrel has chewed on the wires going to it on top of the tank), and ever since then the MDS no longer works now. Makes no sense to me why they would program that to happen just because there is a code popping up.

 

[2003F350]

They do it in an attempt to cut their own liability. I have no idea with OP's issue, we need to know what code it's throwing, but your fuel sensor could possibly some way maybe in a round about way cause issues with low fueling, and running the MDS lean could lead to a destroyed engine. If that happens under warranty then they're paying for a $4k engine install.

 

[MADDOG]

Go get your code(s) read and list them here.

 

[NewBlackDak]

AutoZone reads codes for free. You have to start there with all the computers control and sensors


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[miles01]

New motor in Canada is $12k at motor shop, $15k dealer.
No Autozone in Alberta Canada.

I disconnected the negative battery cable for about 15-20 mins. Reconnected, the check engine light is now off, no messages, and ecno/MDS is working again.
But no satellite radio only FM and AM radio shows up!!WTF.
Repeated battery disconnect / reconnect, all good again.
Only had the reset my Apps on the screen to where I had them before and change the theme back to my preferred colour.

 

[miles01]

It’s been almost two weeks and no issues, no check engine light, no messages, eco light and MDS working fine, and satellite radio working.

I don’t know why it happened, and it only happened once, must have been a computer clich.

 

[JohnnyMac]

Glad it's fixed and thanks for coming back with what you did. Hopefully it'll help someone else down the road.

 

[NewBlackDak]

If it keeps happening, and coming back in shorter and shorter intervals until you finally can’t reset it…
Mine did that. It was a $14 purge canister. Took 10 minutes to install.


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[miles01]

If it keeps happening, and coming back in shorter and shorter intervals until you finally can’t reset it…
Mine did that. It was a $14 purge canister. Took 10 minutes to install.

what is a purge canister
Pics and location please

 

[2021ramlar1500]

what is a purge canister
Pics and location please

It’s been almost two weeks and no issues, no check engine light, no messages, eco light and MDS working fine, and satellite radio working.

I don’t know why it happened, and it only happened once, must have been a computer clich.

 

[2021ramlar1500]

Waiting for delivery of our 1500 Hemi 5.7 L etorque. But we’ve had this problem in our Honda V6 minivan with variable cylinder management. It also shows an Econ light when active and you can feel it Deactivate cylinders although ever so slightly.
So pretty similar technology and for us it was an exhaust oxygen sensor needing replacement. It was also very intermittent at first.
If you live in a remote location it might be worth buying a $40 computer diagnostic handheld device from Amazon. Mine has really come in handy for what seems like the fleet of vehicles I help manage with my college kids

 

[SpeedCoz]

what is a purge canister
Pics and location please

yes same please...very similar issue

 

[douellet20111500]

AutoZone reads codes for free. You have to start there with all the computers control and sensors


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I am in the same boat. I have had my truck to a licensed mechanic who said no codes that pertained to eco mode but my BullyDog programmer always shows a P0420 and occasionally a P0430 and the Autozone reader had the P0420 code as well. My fuel economy has gone to crap by about 50% but the mechanic said his diagnostic said no issues with airflow exhaust while running or driving the truck so i am left with either the O2 sensors or the main computer as far as guy from Autozone was thinking. Any further advice would be appreciated.

 

[2003F350]

I am in the same boat. I have had my truck to a licensed mechanic who said no codes that pertained to eco mode but my BullyDog programmer always shows a P0420 and occasionally a P0430 and the Autozone reader had the P0420 code as well. My fuel economy has gone to crap by about 50% but the mechanic said his diagnostic said no issues with airflow exhaust while running or driving the truck so i am left with either the O2 sensors or the main computer as far as guy from Autozone was thinking. Any further advice would be appreciated.

You need a new mechanic.

First check with P0420 and P0430 is to inspect the wiring to the O2 sensors. If that checks good, replace the O2 sensors, because they're cheap compared to a good converter. If that doesn't fix it, then you need a new converter, preferably OEM or GOOD aftermarket.

Any exhaust/O2 code will cause the eco mode to not function, because the computer has defaulted to its stored fueling table and can't rely on the O2 sensors to tell it if it is running too lean or not (lean = spark knock, which can damage engines), and these are by default usually pretty rich.

If you have a 2011 and haven't replaced a converter or O2 sensors, congratulations, you've had a heck of a run (13 years), but it's probably time to do some maintenance on it.

 

[62Blazer]

The P0420 and P0430 codes are for low catalytic converter efficiency. 420 is bank 1 and 430 is bank 2, so both sides. There are two sets of O2 sensors. The upstream sensors on both sides of the engine are the ones that primarily provide feedback to the ECM in regards how much fuel to the engine, and thus how the engine runs. These will be close to the engine and prior to the exhaust going to the catalytic converters. The downstream O2 sensors will be after the converters and primarily just say if the converters are working and provide very little to no feedback to the ECM that affects how the engine is running. Those downstream sensors are primarily the ones that would cause those codes to be set. Basically what the codes are saying is that the both the upstream and downstream sensors are reading similar results, however the downstream sensors should be reading a much different value because the catalytic converters should be converting the carbon monoxide to carbon dioxide and H20. If the both sets of sensors read the same thing it is saying the converters are "converting" the exhaust gas.
I would look at the STFT and LTFT (short and long term fuel trims). If the truck is getting a lot worse MPG all of the sudden I would expect the fuel trims to read very large negative numbers, like in the -20 or more range. This would indicate the exhaust is way too rich and demanding the ECM to reduce fuel.