AutoCodes – Lexus – B2278 Lexus

B2278 Lexus Code - Engine Switch Circuit Malfunction

Quick Answer

This Diagnostic Trouble Code (DTC) is output when a malfunction is detected between the Main Body ECU and the engine switch, or either of the switches inside the engine switch is malfunctioning. Common causes include Faulty Engine Switch, Engine Switch harness is open or shorted, Engine Switch 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: B2278 Lexus indicates Engine Switch Circuit Malfunction.
Common causes: Common causes include Faulty Engine Switch, Engine Switch harness is open or shorted, Engine Switch 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 2,163

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 Oct 29, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B2278 Lexus Description

This Diagnostic Trouble Code (DTC) is output when a malfunction is detected between the Main Body ECU and the engine switch, or either of the switches inside the engine switch is malfunctioning.

OBDII Code B2278 Lexus - Engine Switch Circuit Malfunction - AutoCodes.com — B2278 Lexus Code - Engine Switch Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC B2278 Lexus?

Faulty Engine Switch
Engine Switch harness is open or shorted
Engine Switch circuit poor electrical connection
Faulty Main Body ECU

How to Fix the DTC B2278 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 B2278 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.

Need more information about the B2278 Lexus code?

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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 B2278 Lexus Code

1. What are the common symptoms of OBDII code B2278 in a Lexus?

- Common symptoms include difficulty starting the engine, intermittent stalling, and the engine failing to switch off properly.

2. What usually causes the Engine Switch Circuit Malfunction (B2278) in a Lexus?

- The primary causes of this code are a faulty ignition switch, damaged wiring or connectors, or a malfunctioning engine control module (ECM).

3. How can I diagnose the Engine Switch Circuit Malfunction in my Lexus?

- Diagnose the issue by conducting a thorough inspection of the ignition switch, checking for damaged wiring or connectors, and using a scan tool to retrieve trouble codes.

4. Can I drive my Lexus with the B2278 code present?

- It is not recommended to drive your Lexus with the B2278 code present, as it can lead to potential safety hazards and further vehicle damage.

5. How serious is the B2278 code in a Lexus?

- The B2278 code should be addressed promptly, as it can cause the engine to behave erratically and may lead to unexpected shutdowns or starting issues.

6. What are some DIY repair tips for fixing the Engine Switch Circuit Malfunction in a Lexus?

- DIY repair tips include checking and replacing the ignition switch if necessary, inspecting and repairing damaged wiring, and resetting the ECM after repairs.

7. How much does it typically cost to repair the B2278 code in a Lexus?

- The cost of repairing the Engine Switch Circuit Malfunction can vary depending on the specific cause, but it may range from $100 to $500 for parts and labor.

8. Can resetting the ECM clear the B2278 trouble code in a Lexus?

- Resetting the ECM may temporarily clear the B2278 code, but it is essential to address the underlying issue to prevent the code from reoccurring.

9. Is it safe to reset the trouble codes without fixing the underlying issue for B2278 in a Lexus?

- It is not recommended to reset trouble codes without fixing the underlying issue, as the problem may persist and potentially lead to more severe issues in the future.

10. How long does it take to repair the Engine Switch Circuit Malfunction in a Lexus?

- The repair time for the B2278 code can vary depending on the specific cause and the expertise of the technician, but it typically takes 1-2 hours to diagnose and fix the issue.