OBD Guide
ENFRDEESPT

B21A1

ECU Reset/Recovery Occurred

B21A1 is an OBD-II diagnostic trouble code meaning: ECU Reset/Recovery Occurred. Common causes: battery disconnection, problems with ecu power supply. Estimated repair cost: ~$56.

Severity
✅ Low
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
~$56 (est.)

Symptoms

  • Reduced engine efficiency
  • Unstable idle
  • Check engine light comes on

Causes

  • Battery disconnection
  • Problems with ECU power supply
  • ECU software failure
  • Wiring harness fault

How to Fix

  1. Check battery connections
  2. Check wiring harness and ECU connectors
  3. Scan the ECU for other errors
  4. If necessary, reflash the ECU

Related codes

P0600P0601P0602

FAQ

What does the B21A1 code mean?

B21A1 is an OBD-II diagnostic trouble code that indicates: ECU Reset/Recovery Occurred

What causes a B21A1 error code?

The most common causes of B21A1 include: Battery disconnection; Problems with ECU power supply; ECU software failure; Wiring harness fault.

How do I fix a B21A1 diagnostic trouble code?

To fix B21A1: Check battery connections. Check wiring harness and ECU connectors. Scan the ECU for other errors. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B21A1?

Limited driving only, diagnose soon

How much does it cost to fix B21A1?

The estimated repair cost for B21A1 is ~$56. Actual cost depends on your vehicle, location, and labor rates.

FRDEESPT

See also: Russian version · NationStat