Turbo/Super Charger Underboost
The HINO-P0299 (Hino) diesel fault code means: Turbo/Super Charger Underboost. This is a serious severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- intermediate
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What Are the Symptoms of HINO-P0299?
- Loss of power, especially under load
- Slow acceleration
- Check Engine light
What Causes HINO-P0299? (Most Likely First)
- Charge-air leak (cracked charge-air cooler, loose clamp or split hose) High
- Variable-geometry turbo vanes or actuator sticking toward the low-boost position High
- Restricted air intake or exhaust Medium
- Boost pressure sensor reading low Low
Can I Still Drive with HINO-P0299?
Short distances only. HINO-P0299 is rated serious severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What does P0299 mean on a Hino?
P0299 means Turbo/Super Charger Underboost. Measured boost pressure stayed below what the engine control module commanded.
Is P0299 a Hino-specific code?
No. P0299 is a generic OBD-II code defined by SAE J2012, so it means the same thing on any vehicle that sets it. The exact conditions Hino uses to set it on its diesels are in Hino service information.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose HINO-P0299?
Compare commanded and actual boost on a scan tool under load.
Pressure-test the charge-air system for leaks.
Command the turbo actuator through its range and check that it moves freely.
Sources 3
This page is built from documented references. Verify against your own service info before repair work.
- California Code of Regulations, Title 13 section 1971.1 (Heavy-Duty OBD)malfunction criteria, section (e)
- SAE J1939-73Application Layer: Diagnostics (defines the SPN/FMI fault-identifier framework)
- SAE J2012Diagnostic Trouble Code Definitions (defines P0299 as a generic OBD-II code)
P0299 on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown:
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