[Pinebro]

I'll try to make this short. Took my new Pathfinder on it first trailer towing trip. From Long Beach, CA to Julian, CA. William Heise Campground.
Everything was going great until about 2 hrs of driving, the Check Engine light went on. I continued to drive. Did not experience any performance issues. Arrived at campground after some mountain climbing. Unhitched trailer. Next day, drove to Julian without trailer. Light is still on.
Two days later, left for home, CEL is still on. No performance issues, ran normal.
Stopped at Rest Stop near Oceanside. Turned off the Pathfinder. Came back a few minutes later. Started the Pathfinder. NO CHECK ENGINE LIGHT!!.
I have spent the last couple days, trying to figure out why the light went off. I wish it stayed on so I could get the system diagnosed.

I would appreciate any feedback.

 

[jman]

That is why I carry a cheap Bluetooth OBDII reader in all my vehicles. Be prepared for next time it happens.
Without a code, we'll just be guessing.

 

[JayArras]

You took a big risk continuing to drive it without knowing the cause. Most times, it's just some code that gets tripped, but it could have been a lot more serious. jman's suggestion is a good one. You also could have stopped at any auto parts store or gas station for a reading. You were lucky.

 

[CaptainBlaze]

The computers store codes for some period of time. You may still be able to read it.

 

[PoManzPathy]

If it wasn't a FLASHING check engine light (indicating a misfire) and there were no performance issues, weird noises, smells, etc. You are perfectly fine.

Like said, you may want to invest in a $20 code reader to keep in the vehicle just for the sake of sanity.

 

[Pinebro]

If it wasn't a FLASHING check engine light (indicating a misfire) and there were no performance issues, weird noises, smells, etc. You are perfectly fine.

Like said, you may want to invest in a $20 code reader to keep in the vehicle just for the sake of sanity.

I took your advice and bought a OBD2 reader.
Hooked it up and it gave me a P0037 fault code.
Look that up and could be a oxygen sensor issue.
thankfully, it's saved that fault code. I took a picture of the screen and I will be taking it to the dealer to fix. It's still under warranty with only 7000 miles. It still should be able to read the fault code with their OBD2 reader.
Thanks so much for the advice.

 

[PoManzPathy]

I took your advice and bought a OBD2 reader.
Hooked it up and it gave me a P0037 fault code.
Look that up and could be a oxygen sensor issue.
thankfully, it's saved that fault code. I took a picture of the screen and I will be taking it to the dealer to fix. It's still under warranty with only 7000 miles. It still should be able to read the fault code with their OBD2 reader.
Thanks so much for the advice.

That's just a heater circuit malfunction on the bank 1 downstream sensor. That's not uncommon for the heating elements to burn out on O2 sensors early on. I had it happen to my 2002 Isuzu Rodeo many years ago when it was relatively new and I swapped out the O2 sensor myself. Like said above, this particular issue will have no adverse effect driving the vehicle this way other than the computer system running in open loop a tiny bit longer waiting for that sensor to heat up on it's own.

 

[Pinebro]

That's just a heater circuit malfunction on the bank 1 downstream sensor. That's not uncommon for the heating elements to burn out on O2 sensors early on. I had it happen to my 2002 Isuzu Rodeo many years ago when it was relatively new and I swapped out the O2 sensor myself. Like said above, this particular issue will have no adverse effect driving the vehicle this way other than the computer system running in open loop a tiny bit longer waiting for that sensor to heat up on it's own.

Update...
Took it to dealer. It turns out there's a TSB on this issue: NTB21025- 2020 Pathfinder code P0037 (HO2S2 Heater) stored. They reprogrammed the ECM per TSB.
Got the car back. Back to normal.

 

[DrDurst]

I'll try to make this short. Took my new Pathfinder on it first trailer towing trip. From Long Beach, CA to Julian, CA. William Heise Campground.
Everything was going great until about 2 hrs of driving, the Check Engine light went on. I continued to drive. Did not experience any performance issues. Arrived at campground after some mountain climbing. Unhitched trailer. Next day, drove to Julian without trailer. Light is still on.
Two days later, left for home, CEL is still on. No performance issues, ran normal.
Stopped at Rest Stop near Oceanside. Turned off the Pathfinder. Came back a few minutes later. Started the Pathfinder. NO CHECK ENGINE LIGHT!!.
I have spent the last couple days, trying to figure out why the light went off. I wish it stayed on so I could get the system diagnosed.

I would appreciate any feedback.

Did you put the Pathy into tow mode with the switch on the lower left side of the dashboard? Did you read the owner's manual where it says to get 500 miles of break-in with the trailer not exceeding 50 mph?

 

[Ianh]

Did you put the Pathy into tow mode with the switch on the lower left side of the dashboard? Did you read the owner's manual where it says to get 500 miles of break-in with the trailer not exceeding 50 mph?

He said he had 7000 miles on it.
Are you saying you have to run first 500 miles in tow mode under 50 mph ?

 

[DrDurst]

He said he had 7000 miles on it.
Are you saying you have to run first 500 miles in tow mode under 50 mph ?

Yes, read the owner's manual under towing.

 

[DrDurst]

Yes, read the owner's manual under towing.

When towing.

 

[Pinebro]

Did you put the Pathy into tow mode with the switch on the lower left side of the dashboard? Did you read the owner's manual where it says to get 500 miles of break-in with the trailer not exceeding 50 mph?

Yes the tow mode switch used. I did mention it was on a TSB.

 

[Ianh]

When towing.

Thanks, have my hitch but haven't put it on yet !
Promise to read manual !

 

[RySp]

Update...
Took it to dealer. It turns out there's a TSB on this issue: NTB21025- 2020 Pathfinder code P0037 (HO2S2 Heater) stored. They reprogrammed the ECM per TSB.
Got the car back. Back to normal.

2020 pathfinder 2,000 miles. Towed 2800lb trailer. Hour in engine light comes on. Got P0037 code. After unhitched for a bit light goes off. Tow again, light comes back on. In tow mode when towing.

At dealer now. They said since light is not currently on, they can't do much as warranty does not cover non-current, past check engine light.

Told them well, I can attach the trailer and bring it in. They didn't like that idea. They said they'll look at it. Been here 2 hours still waiting to see how this ends...

 

[RySp]

2020 pathfinder 2,000 miles. Towed 2800lb trailer. Hour in engine light comes on. Got P0037 code. After unhitched for a bit light goes off. Tow again, light comes back on. In tow mode when towing.

At dealer now. They said since light is not currently on, they can't do much as warranty does not cover non-current, past check engine light.

Told them well, I can attach the trailer and bring it in. They didn't like that idea. They said they'll look at it. Been here 2 hours still waiting to see how this ends...

So came back with the bulletin and reset ECM.
Hope it is all good now.