For reference only. Always confirm part numbers and procedures for your specific vehicle.
Technical guide
BYD Qin L DM-i EV and HEV Modes: Not an Engine Switch
On the BYD Qin L DM-i, HEV mode doesn't mean the engine always runs. How charge, power demand and temperature affect it, and what modes can't explain.
BYD Qin L DM-i EV and HEV modes: the mode name isn't an engine on/off switch
Scope: 2026 Qin L DM-i, China mainland; official website file 20260417; PDF pp. 37–41
HEV doesn't mean always burning fuel
The manual explains that HEV mode uses different drive states depending on charge level and power demand, and that the engine may not run when charge is high and power demand low. So not hearing the engine does not prove the mode selection failed, and seeing HEV on the display is no basis for estimating energy use as if the whole journey ran on fuel. First separate what the display shows from what the car is actually doing. [1]
Automatic changes depend on conditions
This vehicle's information lists factors such as temperature, charge level and power demand that may affect the mode. To understand a particular change, look at the gradient, acceleration demand, temperature and charge level at the time together; don't just compare a single screen before and after pressing the button. This article does not explain how to force-lock EV mode, nor does it recommend changing the operating logic by switching off protective functions. [1]
What modes can't explain
A clear loss of drive, severe unusual vibration or a related fault message needs professional inspection; it cannot be dismissed with "all hybrids do that". The technician should first confirm the vehicle version and the actual symptoms, then diagnose using the matching service information; owners should not carry out extreme charge-level or heavy-load tests. This article gives no remote verdict that any automatic switch is normal. [1]
Sources
[Source 1] BYD China official website: 2026 Qin L DM-i Owner's Manual (in Chinese) (public PDF on the official website)
https://www.byd.com/material/domestic-official/user-manual/dynasty/2026%E6%AC%BE%E7%A7%A6L%20DM-i%E7%94%A8%E6%88%B7%E6%89%8B%E5%86%8C20260417.pdf
Verified: 2026-10-03; page publication date not confirmed.
This article contains information-organising suggestions from the editorial team; it is not a manufacturer repair procedure.
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