Code result
U04B6
Invalid Data Received From Catalyst Heater Control Module
Moderate severity
What it means
A receiving module detected implausible data from the catalyst heater control module (electrically heated catalyst, EHC). Heater current/voltage or temperature values fail plausibility checks and are rejected; emissions warm-up cannot be guaranteed.
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
Module internal fault or sensor input drift
highOne of the most commonly reported causes for this code — check this first.
Software version mismatch after replacement
mediumA plausible cause — test and verify before replacing parts.
Gateway module routing CAN messages incorrectly
lowLess common, but worth ruling out after the more likely causes.
Related help
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