MyTeslaMate
DPB family

DPB_a109_GTMTbuMonError

Power braking assist reduced

What does the DPB_a109_GTMTbuMonError alert mean?

GTM reference frequency error.

What you'll see in your Tesla

  • Power braking assist reduced
  • Braking may require increased effort

What triggers it

Clock signal to GTM peripheral or system timer is faulty. The time passed in the sytem timer is compared with the time passed in GTM peripheral.

When it clears

No internal issue is detected after changing operation cycle. If the condition persists, the DPB module may require replacement.

Potential impact

System will be running in fully degraded state. Braking may require increased effort. Hydraulic Boost Compensation will be triggered when driver pressed brake pedal.

Affected models

Model Y 2025+

Track your Tesla's alerts automatically

Alerts like this reach MyTeslaMate through your car's Tesla telemetry API. MyTeslaMate logs every alert your Tesla reports and turns it into readable history and real-time notifications — hosted TeslaMate with no server to run.