Error Code P00AF on 3.0L Turbo Diesel

[wwtucson]

While driving my 2023 Rubicon with 3.0L turbo diesel up the Grapevine Hill on I-5 North of LA it went into limp mode. Dash error said to "service auto throttle controller". I pulled off and cycled power and it ran normal after that. When I got home I put my OBDII reader on and the error was " P00AF" a turbo boost error code. Has anyone has this issue before. The Jeep only has 5K miles. It was a hot day ( about 95) and I was driving about 75 as I started up the hill with the cruse control on.
Thanks !

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[RicRecon]

Yep. Your oil temps probably exceeded 250-260° and it Went into heat soak. Too much heat in the engine compartment. System did what it was designed to do, derate until it cooled down. There are others that could explain it in more technical terms than I.

I’ve driven the Grapevine many times. and other grades like it. What I do to avoid this. As you approach the grade, switch your display to oil temps, shift into manual mode and then M7, before your temps get too hot and slow down. Your ability to climb that grade at 75 mph is nonexistent. Shift down gears manually trying to keep your rpm’s between 2-3k and your maximum oil temps probably below 245°. As the grade decrease. You can shift up still trying to maintain those rpm’s and temps.

The trick is to manage your rpm’s and speed, letting the transmission do the work for you, while monitoring the oil temps. As you do this more, you’ll begin to really anticipate when to down or up shift. I’ve had to do this on the Grapevine any time of the year, towing or not towing.

 

[HeN2O2]

There is a known problem with turbo performance under these conditions, which exacerbates the engine oil temperature problem. I frequently couldn’t even make the Conejo grade on a cool day at a modest speed. Over time the problem just got worse.

In some cases these Jeeps were left idling for a long time after coming off the assembly line, which caused a hydrocarbon build up in the turbo. There is a service bulletin on the issue that tries a forced regen and then some moderate driving to blow out any debris. In my case it didn’t work and I eventually had the turbo replaced. The good news is it’s covered under the warranty. The bad news is that they have to remove the body to access the turbo, so it’s not a quick job. After replacing the turbo my engine ran cooler going up grades and I haven’t had any problems since, but honestly haven’t driven any steep grades on a hot day to see if the problem is completely resolved.

What RicRecon describes is one way to manage the problem and effectively avoid the error and limp mode, but you will find yourself battling with big rigs in the slow lane at 20 mph on hot days. I installed a Banks iDash Pro to easily monitor several parameters. However, for a 2023 vehicle there is something really wrong with not being to drive up a hill at highway speeds.

 

[rickinAZ]

I installed a Banks iDash Pro to easily monitor several parameters. However, for a 2023 vehicle there is something really wrong with not being to drive up a hill at highway speeds.

Which parameters are you monitoring?

 

[HeN2O2]

Engine oil and coolant temperatures, DPF, Regen, both battery parameters, turbo performance and tranny temp. Using the dash gauges to monitor engine oil and coolant temperatures is somewhat meaningless since they appear to be normal when all is not well. I programmed the Banks iDash to flash a warning when either temperature approached the temperature where everything shut down, which was around EOT of 260 and ECT of 235 To 240.

I have also had CAN Bus issues with constant errors. In the end, there were two loose connections in the PCM harness that also affected engine fan function. A visiting Jeep technician discovered the PCM issue and replaced it, but it still died on me later. The local service manager was trying to diagnose the problem and noticed the fan not functioning correctly. He jiggled the PCM harness and caused the CAN buss error to occur, repeatedly.

Hopefully the latest repairs have saved my Jeep from a couple thermite grenades.

 

[RafterCExplorations]

While driving my 2023 Rubicon with 3.0L turbo diesel up the Grapevine Hill on I-5 North of LA it went into limp mode. Dash error said to "service auto throttle controller". I pulled off and cycled power and it ran normal after that. When I got home I put my OBDII reader on and the error was " P00AF" a turbo boost error code. Has anyone has this issue before. The Jeep only has 5K miles. It was a hot day ( about 95) and I was driving about 75 as I started up the hill with the cruse control on.
Thanks !

Had the same issue just the other day. Pulling Interstate 80 grade over Donner Summit; all the same warnings. An immediate pullover, shut down, short cooling off, restart, all good, except the Check Engine light stayed on. Reset that with OBDII reader, back to normal now with no apparent issues. I do have the iDash, but wife was driving, and not watching the numbers. Outside temps were warm, but not excessive. I think it's possible to "over throttle" these motors, meaning too much pedal input at lower engine RPMs. They definitely need to be driven much more like a truck (semi or heavy diesel pickup), and not allow parameters to go over their max.

 

[HeN2O2]

The P00AF code clears itself after a few drive cycles. Whoever thought limp mode was a good idea should be eviscerated, drawn and quartered.

 

[Ratbert]

Whoever thought limp mode was a good idea should be eviscerated, drawn and quartered.

Absolutely. It's much better to let the engine be destroyed than temporarily reduce its functionality, right?

 

[HeN2O2]

What I have experienced is not a temporary reduction in functionality, but basically a complete loss of power while trying to get to the side of the road on an extremely busy freeway. It’s the immediate loss of power with no warning that creates a significant hazard.

 

[AZThor]

While driving my 2023 Rubicon with 3.0L turbo diesel up the Grapevine Hill on I-5 North of LA it went into limp mode. Dash error said to "service auto throttle controller". I pulled off and cycled power and it ran normal after that. When I got home I put my OBDII reader on and the error was " P00AF" a turbo boost error code. Has anyone has this issue before. The Jeep only has 5K miles. It was a hot day ( about 95) and I was driving about 75 as I started up the hill with the cruse control on.
Thanks !

I had a similar issue going West on I-40 out of Needles. I was doing 70 with the cruise control on. I received the same warning. the Jeep went into limp mode and I could only do 60 MPH. I pulled over, shut off the engine. The Jeep came back to life, it drove normally, but the check engine light remained on. I had just bought the Jeep the day before. I took it back to the dealer who stated that the Turbo needs to be replaced. Luckily it was still under warranty. My buddy owns a Diesel Gladiator with the same issue. He was told the Turbo actuator failed, which means replacing the entire turbo.

 

[Gomer Pyle]

I've lived in the Rockies and the Smoky mountains...I love being in the mountains. I live in TX now and have been looking for reasons to appreciate it more...thanks for the perspective! I don't have long grades that 'microwave' my turbo...we just have extreme heat that'll make you think you live in the devil's fart cloud...

 

[garykk]

I bought this diesel jeep for the power to pull my UTV, it’s great on cool days and flat terrain but even on a cool day it will overheat pulling a grade at highway speed. I didn’t buy this to go up grades at a crawl. Very disappointed in Jeeps dismal cooling system. Yeah I know, I’ll be told to slow down blah blah. I’ve owned several diesel trucks and never had a problem. And then there’s the aux battery issue where folks are told to just put your Jeep on a charger at night. What the hell….I didn’t buy this to make up for Stellantis’s short comings.
this Jeep has turned into a love/ hate relationship.

 

[RafterCExplorations]

I bought this diesel jeep for the power to pull my UTV, it’s great on cool days and flat terrain but even on a cool day it will overheat pulling a grade at highway speed. I didn’t buy this to go up grades at a crawl. Very disappointed in Jeeps dismal cooling system. Yeah I know, I’ll be told to slow down blah blah. I’ve owned several diesel trucks and never had a problem. And then there’s the aux battery issue where folks are told to just put your Jeep on a charger at night. What the hell….I didn’t buy this to make up for Stellantis’s short comings.
this Jeep has turned into a love/ hate relationship.

Jeep didnt put this diesel in the Wrangler for towing. It is not a "heavy duty" type diesel like in a US made truck, it is a European automotive type diesel akin to the VW motors, and was used to get their fuel economy/CAFE numbers up. Within the parameters of its design it works fine but pushed outside its limits, it overheats, etc. Based on its performance capabilities, if it was designed to tow, Jeep would've put a higher tow rating on them.

 

[grimmjeeper]

Jeep didnt put this diesel in the Wrangler for towing. It is not a "heavy duty" type diesel like in a US made truck, it is a European automotive type diesel akin to the VW motors, and was used to get their fuel economy/CAFE numbers up. Within the parameters of its design it works fine but pushed outside its limits, it overheats, etc. Based on its performance capabilities, if it was designed to tow, Jeep would've put a higher tow rating on them.

This diesel in a Ram truck is great for towing moderate loads. Depending on configuration, an EcoDiesel Ram has upwards of 10,000+ lbs capacity.

The problem is that the cooling stack in the JL isn't capable of handling the heat load without a complete redesign. Basically, it's too much engine for the engine bay.

Jeep put it in the JL as a "last chance" option, similar to the Hemi. Diesel is all but dead in the light duty vehicle market. And Jeep grabbed what they had on the shelf that they could run for a couple of years. They basically won't have the ability to run diesel engines going forward and they wanted to do it while they could.

Getting emissions certs for engines takes a lot of time and effort. By using the 3.0, which was offered in other vehicles, they were able to reuse a lot of the effort. They didn't have time or budget to develop a new engine that would only have a run for a few years.

It sucks that the cooling stack isn't capable of handling the 3.0. If it could, the JT would have a much higher tow rating than it does.

Finally, much of the tow rating of the Wrangler is limited by the chassis, not the engine. So even with a lot of torque from the engine, the other limitations of the chassis keeps the tow rating low. The same engine in a JT gets you almost twice the tow rating or more over the JL.

 

[garykk]

Jeep didnt put this diesel in the Wrangler for towing. It is not a "heavy duty" type diesel like in a US made truck, it is a European automotive type diesel akin to the VW motors, and was used to get their fuel economy/CAFE numbers up. Within the parameters of its design it works fine but pushed outside its limits, it overheats, etc. Based on its performance capabilities, if it was designed to tow, Jeep would've put a higher tow rating on them.

Then I guess they should not have rated it for 3500 lbs tow rate. And they don’t work within their “ parameters” as pointed out on this forum, overheating without towing.

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