B2603Airbag/SRS

Seat Belt Pretensioner Loop Fault

B2603 indicates a fault in a seat belt pretensioner deployment loop. The pyrotechnic pretensioner circuit is open, shorted, or out of range, which can prevent it from tightening the belt in a crash.

🚗 Yes, but the seat belt pretensioner may not fire in a crash, so treat it as urgent.

HIGH

severity

🎯 Top Causes, Ranked by Likelihood

#1Loose pretensioner connector$0-$150

40%

An under-seat or B-pillar connector loses contact.

#2Faulty pretensioner squib$150-$500

30%

The pyrotechnic pretensioner unit fails internally.

#3Chafed wiring under the seat$100-$400

20%

Seat travel chafes the harness to the pretensioner.

🩺 Common Symptoms

Airbag/SRS warning light on
Pretensioner may not fire in a crash
Fault after seat movement
Stored pretensioner loop code

💰 Repair Cost: DIY vs Shop

DIY Cost

$0-$200

Shop Cost

$150-$500

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose B2603

1Disarm the SRS system per the service manual

2Reseat the pretensioner connector

3Inspect the under-seat harness for chafing

4Replace the pretensioner only after confirming the loop fault

❓ Frequently Asked Questions

What does B2603 mean?

A seat belt pretensioner circuit is faulty, so the belt may not tighten in a crash.

Can I drive with B2603?

Yes, but the pretensioner may not fire, so fix it promptly.

What causes B2603?

A loose connector, a chafed harness, or a failed pretensioner squib.

🔗 Related Codes

B0020B0022B0001U0151