← Back to Search Severity: Medium

B0678

B0678: Body Control Module (BCM) Security System Malfunction

Fix Cost

$100 - $500

Parts & Labor

Difficulty

3/5

Moderate

1-2 hours

DIY Possible?

❌ No

Pro recommended

📖 What Does B0678 Mean?

The Body Control Module (BCM) has detected a security system malfunction, which may be caused by a faulty BCM, security system sensor, or wiring issue.

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Symptoms

• Alarm system activation
• door locks not functioning
• or vehicle immobilization

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Common Causes

• Faulty BCM
• security system sensor
• wiring issue
• or battery voltage below 10V

Fix Guide

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Possible Solutions

1. Check BCM fuse and replace if blown. 2. Inspect and clean security system sensors. 3. Check wiring for damage or corrosion and repair as needed. 4. Update BCM software if necessary. 5. Replace BCM if faulty.

❓ Common Questions About B0678

Can I drive with code B0678?

You can drive for a short time, but should address code B0678 soon to avoid worsening the problem or failing an emissions test.

How much does it cost to fix code B0678?

The estimated repair cost for code B0678 is between $100 and $500. This includes parts and labor. Prices may vary based on your vehicle's make and model.

Is code B0678 easy to fix myself?

This repair is considered moderate. It may require specialized tools or significant disassembly. If you are not an experienced mechanic, professional help is recommended.

Required Parts

Tools

multimeter wire tester soldering iron

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Need a Pro?

Complex codes like B0678 can be tricky. Don't risk it if you're unsure.

Quick Stats

Severity Medium

DIY Friendly No

Est. Time 1-2 hours

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Related Diagnostic Codes

Other codes that may appear with B0678

B0676 Sequential Code

💡 Why These Codes Are Related:

• Similar Issues: Same root cause or component failure
• Related Problems: Often occur together due to system interactions
• Sequential Codes: Progressive failure stages or multiple sensors
• Same System: Components within the same automotive system