What Volvo codes (P0420, P0299, P0430, P2002) actually mean on Volvo engines — the real cause, the common misdiagnosis, and the honest UK repair cost.
These are the OBD fault codes we see most often on Volvo vehicles in the workshop, with the real cause on Volvo engines rather than the generic textbook definition, plus the honest independent-garage cost.
Volvo fault codes explained
- P0420 — Catalyst efficiency on Volvo — Drive-E 2.0 petrol cat ageing and pre-Drive-E B4204 issues. Typical UK cost £450–£1500.
- P0299 — Turbo underboost on Volvo — D3/D4/D5 actuator failure on the 2.0/2.4 diesel and T5 split charge pipes. Typical UK cost £180–£1300.
- P0430 — Bank 2 cat efficiency on Volvo T6/B6 — XC60/XC90 inline-6 turbo cat aging or oil-burn from worn PCV. Typical UK cost £240–£1800.
- P2002 — DPF efficiency below threshold on Volvo — D3/D4/D5 DPF clog with EGR cooler carbon contribution. Typical UK cost £220–£2600.
Codes are generic across manufacturers, but the fix is not. The same code on a Volvo usually points at a different component than it would on another make, which is why a make-specific diagnosis saves money before any parts are bought.