AutoCodes – Lexus – B27A8 Lexus

B27A8 Lexus Code - Open In Outside Luggage Compartment Electrical Key Antenna Circuit

Quick Answer

The Certification ECU (Smart Key ECU Assembly) generates a request signal and sends it to the Outside Electrical Key Oscillator (for rear side). Common causes include Faulty Outside Electrical Key Oscillator (for rear side), Outside Electrical Key Oscillator harness is open or shorted, Outside Electrical Key Oscillator 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: B27A8 Lexus indicates Open In Outside Luggage Compartment Electrical Key Antenna Circuit.
Common causes: Common causes include Faulty Outside Electrical Key Oscillator (for rear side), Outside Electrical Key Oscillator harness is open or shorted, Outside Electrical Key Oscillator 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 4,929

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 Jan 18, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B27A8 Lexus Description

The Certification ECU (Smart Key ECU Assembly) generates a request signal and sends it to the Outside Electrical Key Oscillator (for rear side). To detect the key near the driver door, the Outside Electrical Key Oscillator (for rear side) creates a detection area towards the area approximately 1.0 m (3.28 ft.) from the back door.
The Diagnostic Trouble Code (DTC) B27A8 is detected by the Certification ECU (Smart Key ECU Assembly) when an open circuit occurs between the Certification ECU (Smart Key ECU Assembly) and Outside Electrical Key Oscillator (for rear side) terminals.

OBDII Code B27A8 Lexus - Open In Outside Luggage Compartment Electrical Key Antenna Circuit - AutoCodes.com — B27A8 Lexus Code - Open In Outside Luggage Compartment Electrical Key Antenna Circuit

What does this mean?

What are the Possible Causes of the DTC B27A8 Lexus?

Faulty Outside Electrical Key Oscillator (for rear side)
Outside Electrical Key Oscillator harness is open or shorted
Outside Electrical Key Oscillator circuit poor electrical connection
Faulty Certification ECU (Smart Key ECU Assembly)

How to Fix the DTC B27A8 Lexus?

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 B27A8 Lexus 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.

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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 B27A8 Lexus Code

1. What does the OBDII code B27A8 mean on a Lexus?

B27A8 indicates an issue with the "Open in Outside Luggage Compartment Electrical Key Antenna Circuit," meaning the system has detected a fault in the circuit responsible for the key antenna near the trunk.

2. What are the symptoms of the B27A8 code on a Lexus?

Common symptoms include the trunk not unlocking with the smart key, difficulty detecting the key fob near the trunk, or the keyless entry system malfunctioning.

3. What causes the B27A8 code to appear?

Possible causes include a damaged or disconnected luggage compartment antenna, a faulty key fob, wiring issues like broken or corroded wires, or a malfunctioning smart key control module.

4. Can a weak key fob battery trigger the B27A8 code?

While unlikely, a weak key fob battery can cause detection issues that mimic antenna problems. Replacing the battery is a good first step to rule out this possibility.

5. How do you diagnose the B27A8 code on a Lexus?

Diagnosis involves visually inspecting the luggage compartment antenna and its wiring for damage, checking for continuity in the circuit, and testing the antenna's operation using a diagnostic scan tool.

6. Is it safe to drive with the B27A8 code active?

Yes, itâ€™s generally safe to drive, but the keyless entry or trunk unlocking features may not work properly, which could be inconvenient.

7. What repairs can fix the B27A8 code?

Repairs may include replacing the luggage compartment antenna, repairing or replacing damaged wiring, or reprogramming or replacing the smart key control module.

8. How much does it cost to fix the B27A8 code on a Lexus?

Repair costs can vary widely but generally range from $100 to $300 for diagnosing and repairing wiring or antenna issues. Module replacement would be more expensive.

9. Can the B27A8 code clear itself?

No, this code will typically remain stored until the underlying issue is repaired and the code is manually cleared with a diagnostic tool.

10. Can I fix the B27A8 code myself?

If youâ€™re comfortable inspecting wiring and connectors, you might be able to fix loose or damaged connections. However, more complex issues like replacing the antenna or module may require professional assistance.