OBD Guide
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B15F9

UART Communication Malfunction

B15F9 is an OBD-II diagnostic trouble code meaning: UART Communication Malfunction. Common causes: wiring harness damage, contact corrosion. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Incorrect engine operation
  • Transmission malfunctions
  • Check Engine Light Illuminates
  • Loss of communication between modules

Causes

  • Wiring harness damage
  • Contact corrosion
  • Malfunction of one of the ECUs
  • Problems with module power supply

How to Fix

  1. Check the integrity of the wiring harness
  2. Inspect contacts for corrosion
  3. Check power supply of modules
  4. Diagnose the operation of the ECU
  5. Replace damaged components

Related codes

U0100U0101U0121

FAQ

What does the B15F9 code mean?

B15F9 is an OBD-II diagnostic trouble code that indicates: UART Communication Malfunction

What causes a B15F9 error code?

The most common causes of B15F9 include: Wiring harness damage; Contact corrosion; Malfunction of one of the ECUs; Problems with module power supply.

How do I fix a B15F9 diagnostic trouble code?

To fix B15F9: Check the integrity of the wiring harness. Inspect contacts for corrosion. Check power supply of modules. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B15F9?

Limited driving only, diagnose soon

How much does it cost to fix B15F9?

The estimated repair cost for B15F9 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat