← Back to Search Severity: Medium

B0742

B0742: Immobilizer System Malfunction

Fix Cost
$50 - $200
Parts & Labor
Difficulty
3/5
Moderate
1-2 hours
DIY Possible?
❌ No
Pro recommended
Category
Body
System

📖 What Does B0742 Mean?

The immobilizer system, which prevents the engine from starting without the correct key, has malfunctioned. This code indicates a problem with the immobilizer system's communication with the engine control module.
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Symptoms

  • Engine won't start
  • key fob not recognized
  • alarm system malfunction
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Common Causes

  • Faulty immobilizer key fob
  • damaged or corroded wiring
  • faulty immobilizer module
  • incorrect key or keyless entry system
Fix Guide
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Possible Solutions

1. Check the key fob's battery level and replace it if necessary. 2. Inspect the wiring and connectors for damage or corrosion and repair or replace as needed. 3. Test the immobilizer module and replace it if faulty. 4. Try using a spare key or keyless entry system if available.

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Common Questions About B0742

Q

Can I drive with code B0742?

A

You can drive for a short time, but should address code B0742 soon to avoid worsening the problem or failing an emissions test.

Q

How much does it cost to fix B0742?

A

The estimated repair cost for code B0742 is between $50 and $200. This includes parts and labor for most makes and models.

Q

Is this code easy to fix myself?

A

This repair is considered moderate. It may require specialized tools or significant disassembly. Professional help is recommended if you aren't an experienced DIYer.

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Need a Pro?

Complex codes like B0742 can be tricky. Don't risk it if you're unsure.

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Related Diagnostic Codes

Other codes that may appear with B0742

💡 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