Volvo check engine codes

Overview

Volvo engines often set codes related to PCV systems, turbo boost, and catalyst efficiency.

Codes notably common on Volvo

• P0171 System Too Lean (Bank 1)
• P0299 Turbocharger or Supercharger Underboost
• P0420 Catalyst System Efficiency Below Threshold (Bank 1)

Volvo specific notes

• On older Volvo five cylinder engines, a clogged PCV oil trap (flame trap) can pressurize the crankcase and push oil past seals. Servicing the trap and hoses is a known maintenance job.

Owner's manuals

Official Volvo owner's manual / owner portal (manufacturer site; we do not host copies).

Recall lookup

Check open Volvo recalls with your VIN at the NHTSA recall lookup.

Sources

• https://www.import-car.com/volvo-flame-trap-or-breather-box-service/
• https://www.nhtsa.gov/recalls

Sources checked October 2026. Bulletins apply only to the models and years they list.

All other codes

These work the same on Volvo as on any vehicle:

P0430 P0300 P0301 P0302 P0303 P0304 P0174 P0440 P0442 P0455 P0456 P0128 P0135 P0141 P0101 P2135 P0401