AutoCodes – Generic – B15F9

B15F9 Code - UART Communication Malfunction

Quick Answer

The Diagnostic Trouble Code (DTC) is stored when a malfunction occurs in the Multi-Media Module Receiver Assembly. Common causes include Faulty Multi-Media Module Receiver Assembly, Multi-Media Module Receiver Assembly harness is open or shorted, Multi-Media Module Receiver Assembly circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B15F9 indicates UART Communication Malfunction.
Common causes: Common causes include Faulty Multi-Media Module Receiver Assembly, Multi-Media Module Receiver Assembly harness is open or shorted, Multi-Media Module Receiver Assembly circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 2,525

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 21, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B15F9 Description

The Diagnostic Trouble Code (DTC) is stored when a malfunction occurs in the Multi-Media Module Receiver Assembly. Open in UART communication line is detected based on radio receiver activation failure.

OBDII Code B15F9 - UART Communication Malfunction - AutoCodes.com — B15F9 Code - UART Communication Malfunction

What does this mean?

What are the Possible Causes of the DTC B15F9?

Faulty Multi-Media Module Receiver Assembly
Multi-Media Module Receiver Assembly harness is open or shorted
Multi-Media Module Receiver Assembly circuit poor electrical connection

How to Fix the DTC B15F9?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B15F9 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B15F9 code?

Need more information on how to fix the B15F9 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B15F9 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B15F9 Lexus — UART Communication Malfunction
B15F9 Toyota — UART Communication Malfunction

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B15F9 Code

1. What are common symptoms of OBDII code B15F9 (UART Communication Malfunction)?

- Common symptoms include issues with the vehicle's transmission, such as rough shifting, hesitation, or the transmission going into limp mode.

2. What are possible causes of the B15F9 code?

- The B15F9 code can be caused by faulty wiring or connectors in the transmission control module (TCM), software issues, or a malfunctioning TCM itself.

3. How can I diagnose the B15F9 code?

- Diagnosis involves using a scan tool to retrieve the code and then conducting a thorough inspection of the TCM wiring, connectors, and software for any faults or damage.

4. Can I still drive my vehicle with the B15F9 code present?

- It is not recommended to continue driving the vehicle with the B15F9 code present as it can lead to further damage to the transmission system.

5. How can I repair the UART Communication Malfunction causing the B15F9 code?

- Repair options may include repairing or replacing damaged wiring and connectors, updating the TCM software, or replacing the TCM itself if necessary.

6. Is it possible to reset the B15F9 code without fixing the underlying issue?

- While you can clear the code with a scan tool, it will likely reappear if the underlying issue causing the UART Communication Malfunction is not addressed.

7. Are there any DIY repair tips for the B15F9 code?

- DIY repair for the B15F9 code may be challenging due to the complexity of the transmission control system. It is recommended to consult a professional mechanic for proper diagnosis and repair.

8. Can a low battery voltage cause the B15F9 code to trigger?

- Yes, low battery voltage can sometimes lead to communication errors between modules in the vehicle, potentially triggering the B15F9 code.

9. Is the B15F9 code specific to a certain vehicle make or model?

- The B15F9 code can be found in various vehicle makes and models that use OBDII systems with UART communication capabilities in their transmission control modules.

10. How much can I expect to pay for repairs related to the B15F9 code?

- The cost of repairs for the B15F9 code can vary depending on the specific cause of the issue, but it is advisable to budget for potential wiring repairs, software updates, or TCM replacement, which can range from a few hundred to over a thousand dollars.