Engine Light on After Cold Start

[Hecmn]

Noticed engine light was on after cold starting (block heater had been plugged in for 2+ hours) and idling for about 15 minutes. Temp was -20F, DEF tank 3/4 full, fuel just above 1/4 tank. Will the engine light come on if fuel gelled and plugged filters?

Moved it into garage at 40F for about 30 hours and restarted - light still on. Any thoughts? 2019 HD2500 with 6.7 CTD.

Thank you for any suggestions.

 

[Trash Panda]

Could be a low fuel rail pressure code, I have had that happen before with some fuel that had clouded, but I’d just be guessing without the code number.

 

[flan]

Anybody’s guess without knowing what the code is…..

 

[Hecmn]

I realize this is a wide-open question given the fact that you can spend less than $100 or several hundred dollars on one, but any recommendations on an OBD2 scanner?

Rule of tools - when you need one, buy it.

 

[Trash Panda]

Cheap is fine. The cheapos on Amazon pull the codes & clear them all the same.

I prefer to buy a good monitor & mount so I can keep tabs on other parameters, as well as clear codes, but for strictly reading codes a cheapo is fine.

 

[Hecmn]

Cheap is fine. The cheapos on Amazon pull the codes & clear them all the same.

I prefer to buy a good monitor & mount so I can keep tabs on other parameters, as well as clear codes, but for strictly reading codes a cheapo is fine.

Trash Panda - thanks for the reply. Just out of curiosity, what other parameters do you keep tabs on?

 

[Trash Panda]

Trash Panda - thanks for the reply. Just out of curiosity, what other parameters do you keep tabs on?

DPF RG%, EGT pre-DPF, and DEF concentration level mainly. I’ll jump around checking others as well.

I like keeping tabs on how the emissions systems are functioning since my 22 has the typical emissions system sensitivity.

 

[flan]

I run a reasonably priced OBD link MX+ and it works great with all my vehicles and also monitors live data on all sensors. It also works with alfaobd if you get into that down the road.

 

[AH64ID]

Noticed engine light was on after cold starting (block heater had been plugged in for 2+ hours) and idling for about 15 minutes. Temp was -20F, DEF tank 3/4 full, fuel just above 1/4 tank. Will the engine light come on if fuel gelled and plugged filters?

Moved it into garage at 40F for about 30 hours and restarted - light still on. Any thoughts? 2019 HD2500 with 6.7 CTD.

Thank you for any suggestions.

Try not to let it idle that long, especially in the cold. 30 seconds or so is all you need before driving. Cold idling isn’t good for the engine.

You could get a CEL for low rail pressure if the filters are plugged, but often the engine just dies.

If the cause of the code was corrected it can take several full drive cycles to clear on its own. You can have a local auto parts store scan codes for free.

I run a reasonably priced OBD link MX+ and it works great with all my vehicles and also monitors live data on all sensors. It also works with alfaobd if you get into that down the road.

Same OBD-II reader I have. Works great with JScan too.

 

[Trash Panda]

Gotta balance cold idling not being good for the truck, and cold driving not being good for the operator, for sure.

I’d be lying if I said I didn’t have a propensity to prioritize the latter at times.

 

[AH64ID]

Gotta balance cold idling not being good for the truck, and cold driving not being good for the operator, for sure.

I’d be lying if I said I didn’t have a propensity to prioritize the latter at times.

Between the block heater, winter front, and electric supplemental heater it’s fairly easy to accomplish both.

 

[Trash Panda]

Between the block heater, winter front, and electric supplemental heater it’s fairly easy to accomplish both.

None of those things make the cab warm when I get in the truck, which is the goal when I’m loading up my wife and 5 month old for a run to town. I don’t have any desire to run a supplemental heater, when 10 minutes of high idle knocks the chill right off.

They definitely speed up the warming process though.

 

[AH64ID]

None of those things make the cab warm when I get in the truck, which is the goal when I’m loading up my wife and 5 month old for a run to town. I don’t have any desire to run a supplemental heater, when 10 minutes of high idle knocks the chill right off.

They definitely speed up the warming process though.

Your sig isn’t filled out, but all gen 4.5 diesels have a 150A supplemental electric heater.

 

[Trash Panda]

Your sig isn’t filled out, but all gen 4.5 diesels have a 150A supplemental electric heater.

Oh, I am aware, I just misinterpreted your post and thought you were referencing an add-on unit such as a webasto.

That’s my mistake

 

[Hecmn]

Try not to let it idle that long, especially in the cold. 30 seconds or so is all you need before driving. Cold idling isn’t good for the engine.

You could get a CEL for low rail pressure if the filters are plugged, but often the engine just dies.

If the cause of the code was corrected it can take several full drive cycles to clear on its own. You can have a local auto parts store scan codes for free.




Same OBD-II reader I have. Works great with JScan too.

Agree on idle time, and normally I am minimizing idle time. Got caught up with some snow clearing and idled it longer than typical. The manual does say to idle about 3 minutes to allow the heaters to complete the post-heat cycle along with avoiding continual operation when the coolant temp is below 140F (60C). The manual also warns against long idle times. As has been pointed out, a little bit of a balancing act.

Hopefully will have a reader from a friend tonight to ID the code. Will follow-up with a post after that.

 

[Hecmn]

Three codes registered. All the same P0562 - System Voltage Low. The first code indicated 'Confirmed', the second 'Pending' and the third 'Permanent'. With engine running, the dash did not have the Battery Saver On/Low Voltage warning, just the check engine light. Batteries are original - 6 years old from time of purchase plus any dealer lot time. Thought I would charge the batteries and then scan for codes again.

I don't see anything specific in the manual about battery charging, just jumping starting. The batteries are wired in parallel, so connecting the charger to the positive post of one battery and the other clip to ground should charge both batteries, correct?

Any other suggestions?

 

[AH64ID]

Agree on idle time, and normally I am minimizing idle time. Got caught up with some snow clearing and idled it longer than typical. The manual does say to idle about 3 minutes to allow the heaters to complete the post-heat cycle along with avoiding continual operation when the coolant temp is below 140F (60C). The manual also warns against long idle times. As has been pointed out, a little bit of a balancing act.

Hopefully will have a reader from a friend tonight to ID the code. Will follow-up with a post after that.

Where do you see the 3 minutes of idle time after starting? I don’t recall ever seeing that. The post-heat cycle is 2 minutes or until you hit >18mph, whichever happens first.

Three codes registered. All the same P0562 - System Voltage Low. The first code indicated 'Confirmed', the second 'Pending' and the third 'Permanent'. With engine running, the dash did not have the Battery Saver On/Low Voltage warning, just the check engine light. Batteries are original - 6 years old from time of purchase plus any dealer lot time. Thought I would charge the batteries and then scan for codes again.

I don't see anything specific in the manual about battery charging, just jumping starting. The batteries are wired in parallel, so connecting the charger to the positive post of one battery and the other clip to ground should charge both batteries, correct?

Any other suggestions?

Yes, that will charge them correctly.

At 6 years old it’s probably time for new batteries, it’s not uncommon for them to only last 3-4 years anymore.

 

[Trash Panda]

Three codes registered. All the same P0562 - System Voltage Low. The first code indicated 'Confirmed', the second 'Pending' and the third 'Permanent'. With engine running, the dash did not have the Battery Saver On/Low Voltage warning, just the check engine light. Batteries are original - 6 years old from time of purchase plus any dealer lot time. Thought I would charge the batteries and then scan for codes again.

I don't see anything specific in the manual about battery charging, just jumping starting. The batteries are wired in parallel, so connecting the charger to the positive post of one battery and the other clip to ground should charge both batteries, correct?

Any other suggestions?

I wouldn’t waste time trying to resuscitate 6 year old batteries, personally,

 

[Hecmn]

Where do you see the 3 minutes of idle time after starting? I don’t recall ever seeing that. The post-heat cycle is 2 minutes or until you hit >18mph, whichever happens first.



Yes, that will charge them correctly.

At 6 years old it’s probably time for new batteries, it’s not uncommon for them to only last 3-4 years anymore.

I've attached pages 37 and 38 from my 2019 Diesel Supplement manual. Page 37 shows what I mentioned on the 3-minute idle time and page 38 shows what you stated about the heaters shutting off after hitting a certain speed. I'm in northern MN and in the mornings the heat cycle will come on the majority of the year. I'm in the habit of idling for the 3 minutes or so before driving. Longer if I'm set up to tow. I've watched the coolant temp many times and after 3 minutes of idling the coolant temp is typically still below 90F.

I agree with you and Trash Panda that it is time for new batteries - can't complain about 6 years. The engine cranked OK, a little longer than normal but like I said it had cold soaked at -20F or colder overnight so not surprising. Wasn't expecting a low voltage code, but happy it wasn't anything more serious. I'm more curious than anything if after charging I still get a low voltage code.

 

[AH64ID]

I've attached pages 37 and 38 from my 2019 Diesel Supplement manual. Page 37 shows what I mentioned on the 3-minute idle time and page 38 shows what you stated about the heaters shutting off after hitting a certain speed. I'm in northern MN and in the mornings the heat cycle will come on the majority of the year. I'm in the habit of idling for the 3 minutes or so before driving. Longer if I'm set up to tow. I've watched the coolant temp many times and after 3 minutes of idling the coolant temp is typically still below 90F.

I agree with you and Trash Panda that it is time for new batteries - can't complain about 6 years. The engine cranked OK, a little longer than normal but like I said it had cold soaked at -20F or colder overnight so not surprising. Wasn't expecting a low voltage code, but happy it wasn't anything more serious. I'm more curious than anything if after charging I still get a low voltage code.

Interesting. I went back and looked again and it’s not in the 2022 manual I have saved, but it is in the 2018 one.

The grid heater operates anytime the manifold temp is 66°F and below, yet Cummins states that a grid heater isn’t needed above 10°F…. Meaning. 10-66°F is Ram driven and likely only emissions based, but it’s hard on batteries and alternators which is why WTS is commonly bypassed.

Cummins also defines excessive idling as anything over 10 minutes per hour of operation, or more than 16.6%.

My 0.02, don’t bother with the 3 minute idle even when towing. 15-30 seconds empty and around a minute towing is plenty, then easily get above 18-19 mph and shutoff the huge amp draw on a cold engine. These engines don’t need a post heat cycle 99% of the time, it takes some really really really cold weather for the post heat to be needed.



As far as the code if it just sat one night at -20°F and set the code I’d be surprised if you see it again in similar conditions with new batteries. If you regularly let the truck sit for over a week in any temp a battery tender, like the NOCO Genius 5, might be a sound investment…. But getting 6 years out of the OEM batteries it sounds like you drive it frequently.