OWNER ANSWER
BYD reversing noise: pedestrian warning sound or a fault?
A steady exterior sound while reversing can be BYD’s pedestrian warning system, AVAS. A parking-sensor beep or a new grinding, scraping or clunking noise is different, so describe the sound and when it occurs before deciding what needs checking.
- Compare what you already heard: steady outside tone, obstacle beep or harsh mechanical noise. Safety note: AVAS alerts nearby pedestrians. Keep it operating, keep people out of the car’s path and avoid extra reversing just to collect a recording; stop safely if braking, steering or control changes.
- Check the AVAS section for your exact model and edition in the sources below.
- If the expected pedestrian sound is absent or a noise has changed, ask BYD to assess that specific symptom.
Original SEAL: when the sound changes normally
The March 2025 RHD handbook says the pedestrian tone grows as forward speed rises to 12 mph (20 km/h), reduces between 12 and 18 mph (20–30 km/h), and stops above 18 mph (30 km/h). Reversing has a continuous tone. So the sound fading at higher forward speed is not, by itself, evidence of a fault.
Use what you already noticed during normal manoeuvring; do not make extra reversing runs to test it. If the expected low-speed or reversing sound is absent, ask BYD to check the AVAS output. These figures apply to this original-SEAL edition; use the linked handbook for another BYD or generation.
What to expect
You have distinguished the documented pedestrian-warning tone from a parking alert or new mechanical noise. The expected AVAS sound remains available; an absent or changed sound needs the specific check below.
If that did not work
Ask BYD to check AVAS if its expected sound is absent. For a new mechanical noise, request inspection of the affected brake, wheel or drive-system symptom; changed vehicle control needs assistance.
What the seven handbooks agree on
The cited ATTO 2, original ATTO 3, EVO, DOLPHIN, SURF, original SEAL and SEALION 7 sections describe a continuous reversing warning sound. Their optional controls, speed thresholds and missing-sound checks differ, so use the matching edition.
What to describe
Tell the repairer whether it was only in Reverse, also in Drive, or linked to braking or steering. Recent tyre or servicing work and existing warning messages are useful context.
Related links
Source: ATTO 2 handbook (PDF 130–131; printed 129–130) (BYD UK) · ATTO 3 handbook (PDF 133–134; printed 132–133) (BYD UK) · ATTO 3 EVO handbook (PDF 172; printed 171) (BYD UK) · DOLPHIN handbook (PDF 134; printed 133) (BYD UK) · DOLPHIN SURF handbook (PDF 116–117; printed 115–116) (BYD UK) · SEAL handbook (PDF 137–138; printed 136–137) (BYD UK) · SEALION 7 handbook (PDF 164–165; printed 163–164) (BYD UK). Checked 22 October 2026.
Original-SEAL speed behaviour reviewed 13 November 2026 against RHD EN-250305 handbook, PDF 137–138 (BYD UK). No disabling procedure is needed for this check.