P0299 on Cadillac
Turbo/Supercharger Underboost Condition
P0299 on Cadillac vehicles indicates turbo/supercharger underboost condition. Au7o has documented this code across 5 Cadillac models — most commonly on ATS, CT4, CT6. P0299 means the engine computer detected an underboost condition — the turbocharger or supercharger is producing less boost pressure than the PCM expects for the given conditions. The computer compares the manifold/boost pressure sensor reading to a target based on engine load, and when actual boost falls short, it sets this code. The most common real-world cause is a leak somewhere in the intake/charge-air path. You'll typically feel reduced power or sluggish acceleration, and the engine may go into a reduced-power mode. Typical repair costs on Cadillac range from $200 to $3,500, depending on the specific model and root cause.
Common Causes of P0299
- •Boost/intake leak (cracked or loose charge-air hose or intercooler)
- •Faulty or sticking turbo wastegate or actuator
- •Stuck or clogged variable-geometry turbo vanes (VGT)
- •Faulty boost pressure or MAP sensor
- •Leaking or disconnected vacuum/boost control lines
- •Restricted air intake or clogged air filter
- •Failed boost control solenoid
- •Worn or failing turbocharger
P0299 on Cadillac by Model
Cadillac ATS(1 issue)
- 2.0T LTG Turbo System Issues - PCV and Wastegate2013-2019
The 2.0L turbocharged LTG engine in 2013-2019 ATS models shares the same PCV valve cover failure, wastegate actuator issues, and turbo oil line problems as the CTS 2.0T. The PCV system integrated into the valve cover fails between 50,000-100,000 miles causing oil consumption and vacuum leaks. The wastegate actuator can fail causing boost control issues. Same root cause and fixes as the CTS 2.0T.
Cadillac CT4(2 issues)
- Twin-Turbo V6 Squealing Noise on Acceleration2022-2024
CT4-V Blackwing models with the 2.7L twin-turbo V6 (L3B) can develop a squeaking or squelching noise during acceleration, particularly once the engine is warm. The noise is often traced to turbocharger-related components including wastegate actuators, boost pipes, or turbo bearings. Some cases have required turbo replacement under warranty. The issue varies in severity from cosmetic noise to indicating actual component wear.
- 2.0T LSY Engine - Valve Cover/PCV and Coolant Issues2020-2025
The CT4 base model uses the 2.0T LSY engine which shares the valve cover/PCV failure and turbo coolant line concerns found in the XT4. The PCV system integrated into the valve cover can fail between 40,000-80,000 miles, causing oil consumption, vacuum leaks, and rough idle. Turbo coolant line connections can develop slow leaks. The CT4-V uses a 2.7T engine (L3B) with different issues. The CT4-V Blackwing uses the 3.6L Twin-Turbo (LF4) which is bespoke and generally reliable.
Cadillac CT6(2 issues)
- 4.2L Blackwing Twin-Turbo V8 Intercooler Coolant Leak2019-2020
The hand-built 4.2L "Blackwing" twin-turbo V8 in the CT6-V and CT6 Platinum suffers from intercooler coolant leaks at the charge cooler connections. The air-to-water intercooler system uses plastic quick-connect fittings that become brittle from heat cycling. Coolant loss leads to reduced intercooler efficiency and elevated charge air temperatures, causing the ECU to pull timing and reduce power output. In severe cases, coolant can enter the intake manifold.
- 3.0L Twin-Turbo V6 Wastegate Actuator Failure2016-2020
The twin-turbo 3.0L V6 (LGW) can develop wastegate actuator issues where the electronic wastegate sticks or fails to regulate boost pressure properly. This can result in either overboosting (which triggers limp mode) or underboosting (causing reduced power). The actuators are exposed to extreme heat cycles.
Cadillac CTS(1 issue)
- 2.0T LTG Turbo System Issues - PCV and Wastegate2014-2019
The 2.0L turbocharged LTG engine in 2014-2019 CTS models has several documented issues. The PCV system integrated into the valve cover is prone to failure, causing oil consumption, rough idle, and boost leaks. The turbo wastegate actuator can fail, causing overboost or underboost conditions. The turbo oil feed and drain lines can clog, starving the turbo of lubrication. These issues typically appear between 50,000-100,000 miles. The LTG engine is otherwise reliable when these wear items are addressed.
Cadillac XT4(1 issue)
- 2.0T LSY Engine - PCV and Turbo Coolant Line Issues2019-2025
The XT4 uses the 2.0T LSY engine which is an evolution of the LTG found in the ATS/CTS. The LSY has improved reliability but shares some issues including PCV system problems and turbo coolant line leaks. The turbo coolant lines can develop leaks at the connections, causing coolant loss and potential turbo damage from overheating. The PCV valve/cover can fail causing oil consumption. These issues typically appear between 40,000-80,000 miles.
Looking for P0299 on a different make?
View P0299 across all makes →Frequently Asked Questions
What does P0299 mean on Cadillac?▼
P0299 stands for "Turbo/Supercharger Underboost Condition." P0299 means the engine computer detected an underboost condition — the turbocharger or supercharger is producing less boost pressure than the PCM expects for the given conditions. The computer compares the manifold/boost pressure sensor reading to a target based on engine load, and when actual boost falls short, it sets this code. The most common real-world cause is a leak somewhere in the intake/charge-air path. You'll typically feel reduced power or sluggish acceleration, and the engine may go into a reduced-power mode. On Cadillac specifically, this code is documented across 5 models.
What causes P0299 on Cadillac vehicles?▼
Common causes on Cadillac: Boost/intake leak (cracked or loose charge-air hose or intercooler), Faulty or sticking turbo wastegate or actuator, Stuck or clogged variable-geometry turbo vanes (VGT), Faulty boost pressure or MAP sensor, Leaking or disconnected vacuum/boost control lines. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0299 on a Cadillac?▼
Repair costs on Cadillac range from $200 to $3,500, depending on the specific model and root cause.
Which Cadillac models have P0299 documented?▼
Au7o has documented P0299 on 5 Cadillac models: ATS, CT4, CT6, CTS, XT4.