Code result
P20BA
Reductant Heater A Control Performance
Moderate severity
What it means
The reductant (AdBlue/DEF) tank or line heater A does not reach the expected temperature within the calibrated time window. In cold weather frozen DEF blocks the SCR dosing system and the engine enters a no-restart state after ignored warnings.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Heater element failed
highOne of the most commonly reported causes for this code — check this first.
Tank temperature sensor drift
mediumA plausible cause — test and verify before replacing parts.
Heater relay failed
lowLess common, but worth ruling out after the more likely causes.
Related help
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