P28C3EVAP System High Load Purge Line B Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Under boost the intake manifold is above ambient pressure, so turbo engines add a high-load purge path: compressed air drives an ejector (venturi) that draws canister vapour into the compressor inlet, with check valves keeping boost out of the tank side. CARB requires every purge path to be checked for missing flow, from 2021 including disconnected lines, unless the high-load path carries under 1 percent of purge mass on the US06 cycle. P28C3 is the function check of a second such line, B. Line A is P04F0, used for example by Genesis on the 2.5T with a dual purge ejector that clogs with debris. No manufacturer publicly documents P28C3 or names line B. Volvo's 2019–2020 Dual Purge action shows the typical fault: a check valve upsetting ejector flow at high load, logging a code and the MIL.
- What you may notice
- MIL on, usually without any change in driving behaviour
- EVAP readiness not completed
- Occasional fuel smell after long full-load driving
- Likely causes
- LikelyCheck valve in high-load line B sticking, leaking or fitted the wrong way round
- PossibleLine B to the compressor inlet pulled off, cracked or kinked
- PossibleEjector nozzle blocked by debris or oil residue
- RareLeak in the boost-side hose that drives the ejector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.