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U0621 Lost Communication With Exhaust Gas Temperature Sensor Bank 2 Sensor 1

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modeNo

U0621 mirrors U061F on bank 2: messages from the first exhaust temperature sensor of the second cylinder bank no longer reach the controller, so the code only appears on V engines or other layouts with two exhaust paths. Bentley documents it for the V8 in the Continental GT, GTC and Flying Spur, model years 2020 to 2023 (bulletins 2065698/1 and 2065698/2): the emission warning lamp is lit and the fault memory shows U0621, often alongside U061F, as intermittent or static. The cause was the sensor harness routed close to the subframe and worn through on a bracket inside the wheel-arch liner; the repair is mending the wires and re-securing them so they cannot touch nearby parts again. GM's SENT diesel tables contain no bank 2 code. Analog circuit faults at this position are P0547 to P0549.

Likely causes

Harness rubbed through on the subframe or a wheel-arch bracket

Electronics of the bank 2 sensor failed

Connector not latched or corroded

Symptoms

Emission warning lamp on
Code logged as intermittent first, later static

Repair estimate

DifficultyMediumDIY possible

Parts and labour€60–500

Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

egt sensor bank 2 sensor 1sensor wiring

References: static.nhtsa.gov, static.nhtsa.gov, sensience.com.