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Turbo and forced inductionGeneric OBD-II codeUrgency: Garage soon

P0299 on Opel: causes and affected engines

P0299 means: turbocharger or supercharger "A": insufficient boost pressure (underboost).[1][2] Opel has 12 documented faults that can trigger it, across 8 engines, including 1.3 Multijet, 1.9 JTD/Multijet and 2.4 JTD, 2.0 CDTI and 2.0 DTI and 2.2 DTI. Only a diagnosis can confirm the cause on your car.

Documented faults
12
that can trigger it
Engines
8
used by Opel, with at least one of them
Opel models
24
with at least one of these faults
Urgency
Garage soon

2 sourcesHow we work

Documented faults in Opel engines that can trigger P0299

Grouped by engine or model, from most to least important. These are faults with the turbo and with the EGR valve: not all of them will necessarily set the code, and only a diagnosis confirms the cause on your car.

1.9 JTD/Multijet and 2.4 JTD

In Astra H, Signum, Vectra C and Zafira B

Common causes of P0299 on any make

From most to least likely, according to the sources.

  1. 1Air leaks in the boost hoses or the intercooler, from a split hose or a loose clamp: this is the most common cause.[1][2]
  2. 2Faulty wastegate or its actuator, or a seized turbo, which do not regulate the pressure properly.[1][2]
  3. 3Worn or faulty turbo.[1][2]
  4. 4Blocked intercooler or intake.[2]

What to check first

The first diagnostic steps, from the most likely and cheapest to check to the most expensive.

  1. 1First check the boost hoses and the intercooler: cracks, oil at the joints and loose clamps. This is the most common cause and the cheapest to repair.[1][2]
  2. 2With a diagnostic tool, compare the boost pressure requested by the control unit with the pressure measured by the sensor while you accelerate.[2]
  3. 3Check that the wastegate actuator (or variable geometry actuator) moves and that its rod travels the full stroke, and check the solenoid valve that controls it.[1][2]
Full guide to P0299: symptoms, diagnosis and whether you can drive

Frequently asked questions

Which Opel engines have faults that can trigger P0299?

1.3 Multijet (2 faults), 1.9 JTD/Multijet and 2.4 JTD (2 faults), 2.0 CDTI (2 faults), 2.0 DTI and 2.2 DTI (2 faults), 1.4 Turbo (1 fault) and 2.3 dCi (M9T) (1 fault). Each fault has its own page with the affected years and versions, the symptoms and the repair cost.

What does code P0299 mean on a Opel?

Turbocharger or supercharger "A": insufficient boost pressure (underboost). The engine control unit has detected that the turbo is not delivering the expected boost pressure: the actual pressure falls below what the engine management requests. That is why, to diagnose it, the requested pressure is compared with the measured pressure using a diagnostic tool. It is a generic OBD-II code: it means the same on a Opel as on any other make.[1][2]

Can I keep driving with P0299?

Garage soon. You can normally get to the garage by driving gently, often in degraded mode, but you should not carry on using the car as normal: the fault can end up causing more serious engine damage.[1][2]

Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. Qué significa el código P0299Autodoc Club · Technical documentation · consulted 2 October 2026 · in Spanish
  2. P0299: Turbocharger/Supercharger A Underboost ConditionCarista · Technical documentation · consulted 2 October 2026