C2171Tyre-pressure sensor IDs not registered

• Toyota/Lexus code · Tyre pressure (TPMS)
• Lights a warning lamp

How the car detects it

The tyre-pressure system has no sensor IDs stored, typically after the control unit was replaced or new sensors were fitted. The IDs must be registered with a scan tool. Until it is fixed, check tyre pressures yourself with a gauge.

What you may notice

• Tyre-pressure warning light blinks, then stays on

Likely causes

• PossibleIDs not registered after a sensor or control unit replacement

Sources

• share.qclt.com › 036007.pdf
• toyota-club.net › be_tpms_4d.htm
• moderntiredealer.com › tpms-toyota-ch-r-2018-2020

Backed by at least two independent sources.

From Obdaryn's Toyota/Lexus pack, exactly as the app shows it, with the public sources above. Guidance only; confirm with a workshop.