Code result
P202F
Reductant/Regeneration Supply Control Circuit Range/Performance
Moderate severity
What it means
The control line that gates the DEF supply pump or the regeneration heating circuit does not respond as commanded — duty cycle, current draw, or response time off-spec.
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
Supply relay aged or pitted contacts
highOne of the most commonly reported causes for this code — check this first.
Supply pump motor brushes worn
mediumA plausible cause — test and verify before replacing parts.
Sensor element aged beyond calibration window
lowLess common, but worth ruling out after the more likely causes.
Related help
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