P0456 on Your 2024 Audi Q5
A P0456 code on your 2024 Audi Q5 signals the ECM has detected a very small leak (0.020-inch equivalent) in the EVAP system. Your Q5 uses the VW Group's EVAP architecture with a Leak Detection Pump (LDP) and N80 purge valve. On a new model, P0456 is typically minor and fully covered by warranty.
The 2024 Q5's 2.0L TFSI turbocharged engine shares its EVAP platform with other VW/Audi models, meaning the diagnostic approach is well-established.
Likely Causes
- Gas cap not fully seated (33%) — The simplest and most common cause.
- Software calibration sensitivity (22%) — ECM updates may adjust EVAP thresholds.
- Factory EVAP connection variance (18%) — A fitting not 100% engaged from assembly.
- N80 purge valve irregularity (15%) — Though uncommon on new vehicles, a marginal N80 is possible.
- LDP variance (7%) — A marginal Leak Detection Pump reading.
- New seal break-in (5%) — Fresh seals needing thermal cycling.
What to Do
- Check the gas cap — Remove, inspect, reinstall firmly.
- Audi dealer visit — Full warranty, zero cost. ODIS diagnostics and TSB check.
- Software update — Pending ECM calibrations may resolve the issue.
- Physical repair if needed — Under warranty.
Cost
- Under warranty: $0—covered through 2028 (basic) and 2032 (emissions)
- Gas cap (DIY): $15–$35
Warranty
Your 2024 Q5 carries Audi's 4-year/50,000-mile basic warranty through 2028 and federal emissions coverage for 8 years/80,000 miles through 2032. Let the dealer handle it at no cost.