Check Engine Light

My truck is a 2022 Frightliner Cascadia. I got it new and it now has just shy of 62,000 miles. I’ve been super happy with this truck and it’s only had one issue that I’m worried about.

The check engine signal came on at about 20,000 miles. I took it into the shop and they hooked up their magic diagnostic computer. They said they “reset a sensor”, not to worry and the light went off. Then at about 40,000 miles it came on again. Took it into the shop and got the same explanation. Now it’s on for a third time since about 55,000 miles. The shop asked me if I noticed anything wrong with the trucks performance. I told them no and they said to just bring it into the shop again next time at the yard.

Anybody know what’s happening here and why the check engine signal keeps coming on?

Bruce the answer to your question is not an easy one. It could be low voltage for a few seconds to one of the many sensors all over it, a sensor going bad, a loose connection to a sensor, etc. Try turning the truck off. Turn the key on and let it cycle through all its checks. Repeat three times. If it was something weird and momentary it should reset the lite without going to the shop.

Are you sure it is the check engine lite, or could it be the mil lite?? Mil lite will be the emissions system.

Not sure if they have changed things but it used to be with either of those lites on the truck would not regen itself. That will lead to bigger issues.

If it is the yellow advisory light indicator on the dash, all you can do is "shop it". Nothing you can repair yourself. Check to see if there are any associated fault codes. It could stay on for a minute or six months due to many causes: clogged filter, stray voltage, a speck of dust on a sensor. If the gauges are normal and the engine operates I would tell the shop personnel again the next time. If it starts blinking or turns color to red, then that'll be an immediate problem. Keep rolling

I forgot to reply to this earlier, but one of the tab options in the dash is diagnostics it looks like a wrench. Select that then scroll through the options looking for a code, if it finds one Google it and see what it is for.

We haven't reached the point where the onboard AI will alert you that the AE-35 unit will go to 100% failure within 72 hours (yet). Your Freightliner will let you view faults (error codes) as others have noted. Your carrier's service department may have your truck configured to read your truck's codes while you're on the road. I once got a check engine light and when I pulled over and called CRST's service department they put me on hold for a few minutes and then informed me that it was a faulty sensor and to proceed with my delivery. They just added it to the list of things they would take care of on my next PM.

Most of the time when my truck's dash lights up like a Christmas tree it's just a sensor or emissions issue. NEVER ignore a dash light but use your best judgement about where and when to deal with it. I'll jump on a dash light much more quickly if I'm in west Texas in the summer (hours away from help, 130 degree temps, spotty cell coverage and nothing but rattlesnakes to keep me company) than I would between Portland, OR and Salem, OR (six truck stops in 35 miles, lows above freezing and 100% cell phone coverage).

Before proceeding with a CE light:

Consider your truck. Is there a history of one type of problem? Your truck's mileage - over 50,000 miles is more serious than under 5,000 because there are more things that will break the more miles you turn.

Where are you at vs. where you are going. Will proceeding on your trip put you further away from a terminal , a truck stop or some place that can help you or closer? What are the relative risks? Temperature, cell phone coverage, traffic, weather or road conditions should all be considered.

Take a look. Pop the hood and do an extended truck inspection to look for clues about the problem. If you don't see anything too critical (leaking radiator fluid, broken fan belt, smoke or fire) you can at least be more confident if you decide to proceed.

True, CRST has all their trucks set up to be "read" while on the road, anyplace in the US. lol Had to make a couple calls to service, when some lights came on, that really shouldn't have for the circumstances.

My 2019 has a reoccurring NOX sensor issue. The standard line is, as long as it's the amber engine shaped light, and not the one that says "eng" or the red one, it's ok to cautiously proceed after checking fluids, belts, or any other obvious easy roadside fixes.

Usually mine goes away after 10-15 key cycles. I'd have it hooked up and checked sooner than later, but I wouldn't give up a load to make a shop detour over it.

This frequently happens in my 2018. The shop has me shut off the batteries for 15 minutes or so to reset. Also, they can remotely read any error code I might get. When illuminates and everything is operating WNL, I power down the bats and let them know so they can verify their are know issues.