← Back to Search Severity: High

B0078

B0078: Immobilizer System Malfunction

Fix Cost
$100 - $500
Parts & Labor
Difficulty
3/5
Moderate
1-2 hours
DIY Possible?
❌ No
Pro recommended
Category
Body
System

📖 What Does B0078 Mean?

The immobilizer system has malfunctioned, preventing the vehicle from starting or running. This code indicates a problem with the immobilizer system's communication with the engine control module.
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Symptoms

  • Vehicle will not start
  • or will start and then stall
  • or will not run due to immobilizer system malfunction
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Common Causes

  • Faulty immobilizer key fob
  • faulty immobilizer system module
  • faulty wiring or connectors
  • software issue
Fix Guide
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Possible Solutions

1. Check the immobilizer key fob's battery level and replace if necessary. 2. Check the immobilizer system module for any signs of physical damage or corrosion. 3. Inspect and clean the wiring and connectors for any signs of damage or corrosion. 4. Update the vehicle's software if necessary. 5. Replace the immobilizer system module if none of the above steps resolve the issue.

Required Parts

Tools

multimeter wire tester diagnostic scanner
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Need a Pro?

Complex codes like B0078 can be tricky. Don't risk it if you're unsure.

Quick Stats

Severity High
DIY Friendly No
Est. Time 1-2 hours
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Related Diagnostic Codes

Other codes that may appear with B0078

💡 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