Engine check light - Code P0299

Darron · Nov 25, 2020

Driving my new 2020 Ram 2500 CTD (just under 2k miles), the orange "engine check indicator" lit up with an audible ding. This was about 5 miles down the freeway after leaving the wash-it-yourself carwash which involves use of a pressure sprayer. Driving was unaffected. Light stayed on for about 48 hours and turned off by itself, but only when I started to drive to the local dealership to have it checked! I went in anyway to retrieve the code:

P0299 - turbocharger underboost.

I snapped a shot of the service guy's screen (seen below).

I've been driving for an additional day. Light has not come back on. Driving well. I figure enough water got pulled up the air intake and into the filter to restrict airflow. Being that I am in Oregon, it's intermittently raining, and highs are in the 40s, it probably took a loooong time (2 days) to dry out and now it's fine. Any other thoughts?

Anyone know of a relatively cheap but good quality OBD tool to retrieve these codes? I'm willing to spend up to $80 or so if it's good quality and conveniently small.

SniperDroid · Nov 26, 2020

For years I used a scanner called OBD-MX for checking codes on out vehicles. In the F250 Turbo Diesel we had, I used it to monitor the critical engine systems when we were towing. While I probably never buy a diesel again, it was always handy to have since my work truck gets about 40K a year of use....

crash68 · Nov 26, 2020

Darron said:
I've been driving for an additional day. Light has not come back on. Driving well. I figure enough water got pulled up the air intake and into the filter to restrict airflow. Being that I am in Oregon, it's intermittently raining, and highs are in the 40s, it probably took a loooong time (2 days) to dry out and now it's fine. Any other thoughts?

Unless you blasted the water directly into the airbox inlets I doubt the air filter was wet enough to cause the problem. If the air filter was soaked, you'll see signs that it was wet.
Turbo underboost would be the ECM is not reading enough commanded boost. The ECM calculates the amount of boost then compares that to the MAP reading. The problem is more likely a sensor or turbo actuator.
The OBDLink MX+ is good code reader to look at, it is compatible with Android, Apple and PC. It comes with expanded diagnostic capabilities. Its also recommended if you decide to use AlfaOBD down the road.

Flyboy7 · Dec 5, 2020

i just had my light come on, less than 500 miles on the cummins. no idea why.

Darron · Dec 5, 2020

Flyboy7 said:
i just had my light come on, less than 500 miles on the cummins. no idea why.

Do you know the code that triggered it?

Flyboy7 · Dec 6, 2020

Darron said:
Do you know the code that triggered it?

Found out today, P029900, low boost. Was driving with wet snow falling yesterday but gimme a break.

wec728 · Dec 2, 2022

crash68 said:
Unless you blasted the water directly into the airbox inlets I doubt the air filter was wet enough to cause the problem. If the air filter was soaked, you'll see signs that it was wet.
Turbo underboost would be the ECM is not reading enough commanded boost. The ECM calculates the amount of boost then compares that to the MAP reading. The problem is more likely a sensor or turbo actuator.
The OBDLink MX+ is good code reader to look at, it is compatible with Android, Apple and PC. It comes with expanded diagnostic capabilities. Its also recommended if you decide to use AlfaOBD down the road.

mtnrider · Dec 2, 2022

What air filter are you running in the truck? Have you replaced it with a non-oem?

.

wec728 · Dec 2, 2022

I have a 2021 ram 6.7, I had it detailed with 10k on the truck. The day I picked it up the P0299 code came on and I had it reset. Every single time I use a pressure washer I pull that same code. The dealership replaced my DEF heater and it changed nothing. My truck currently has the code and I’m waiting for my next appointment. The truck now has 26k miles on it and I’ve never been impressed with this diesel. I feel like the Cummins is way to restricted.

mtnrider · Dec 2, 2022

wec728 said:
I have a 2021 ram 6.7, I had it detailed with 10k on the truck. The day I picked it up the P0299 code came on and I had it reset. Every single time I use a pressure washer I pull that same code. The dealership replaced my DEF heater and it changed nothing. My truck currently has the code and I’m waiting for my next appointment. The truck now has 26k miles on it and I’ve never been impressed with this diesel. I feel like the Cummins is way to restricted.

Are you using the pressure washer in the engine bay? Are you running a factory OEM air filter? Your active air door on the air box may not be work correctly or could have been damaged?

DEF heater has nothing to do with the code you are getting.

.,

crash68 · Dec 2, 2022

wec728 said:
I have a 2021 ram 6.7, I had it detailed with 10k on the truck. The day I picked it up the P0299 code came on and I had it reset. Every single time I use a pressure washer I pull that same code. The dealership replaced my DEF heater and it changed nothing. My truck currently has the code and I’m waiting for my next appointment. The truck now has 26k miles on it and I’ve never been impressed with this diesel. I feel like the Cummins is way to restricted.

If your pressure washing the engine and getting that P0299(turbo under boost) code, check the MAP sensor.
I doubt the engine is restricted too much as there usually not much gained by deleting them. You also have to contend with the transmission torque management that tries to keep the engine from tearing the trans apart. Just driving a Cummins does seem a little lackluster until you have a load behind it.

wec728 · Dec 4, 2022

mtnrider said:
Are you using the pressure washer in the engine bay? Are you running a factory OEM air filter? Your active air door on the air box may not be work correctly or could have been damaged?

DEF heater has nothing to do with the code you are getting.

.,

wec728 · Dec 4, 2022

crash68 said:
If your pressure washing the engine and getting that P0299(turbo under boost) code, check the MAP sensor.
I doubt the engine is restricted too much as they’re usually not much gained by deleting them. You also have to contend with the transmission torque management that tries to keep the engine from tearing the trans apart. Just driving a Cummins does seem a little lackluster until you have a load behind it.

wec728 · Dec 4, 2022

I did not pressure wash the engine. It doesn’t seem to happen when you go through a touch less wash only when I use the wand.

Engine check light - Code P0299

Darron

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SniperDroid

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crash68

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Flyboy7

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Darron

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Flyboy7

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wec728

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mtnrider

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wec728

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mtnrider

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crash68

ACME product engineer

wec728

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wec728

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wec728

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