All Body Security DTC Codes — Complete OBD-II Diagnostic Guide (2026)

This comprehensive reference covers every Body Security diagnostic trouble code (DTC) — 2 codes total. Each code includes what triggers it, common symptoms, step-by-step diagnostic procedures, and repair guidance.

2DTC Codes
1Medium
1Low

Detailed DTC Code Guides

B1600: The B1600 code indicates that the Passive Anti-Theft System (PATS) has received an incorrect key code, preventing the vehicle from starting. This code is typically triggered when the PATS system detects a mismatch between the expected and actual key code. The PATS system uses a transponder chip in the key to verify the key's authenticity and authorize the vehicle to start.

low ⏱️ 30-60 minutes ⚠️ You can still drive with this code, but it may cause issues with starting the vehicle, potentially leading to safety hazards if the vehicle stalls in traffic.

Fix B1600 code with our detailed, step-by-step guide. Covers Ford, Honda, and Chevy models. Free DIY repair guide with tools, parts, and cost estimates to...

Diagnostic steps:
  1. Step 1: Verify Key Integrity
  2. Step 2: Monitor PATS System Live Data
  3. Step 3: Inspect Transponder Chip
  4. ...see all 4 steps →
Read full diagnostic guide →

B2799: The B2799 code tells the vehicle’s control module that the immobilizer (anti‑theft) system is not communicating correctly. It usually means a key‑recognition problem, a wiring fault, or a faulty immobilizer control unit.

medium ⏱️ 30-60 minutes ⚠️ Can you still drive? Yes, but the engine may not start until the issue is cleared.

B2799 indicates an anti‑theft system fault. Learn why it flashes, which models are affected, and how to repair it yourself with cost estimates and a quick...

Diagnostic steps:
  1. Verify key and battery
  2. Scan for related codes and check live data
  3. Inspect wiring harness and connectors
  4. ...see all 5 steps →
Read full diagnostic guide →

Understanding Body Security Codes

Body Security diagnostic trouble codes are set by your vehicle's onboard computer (ECU/PCM) when it detects a problem in the security system. Here's what you need to know:

  • How codes are triggered: Sensors monitor security performance. When readings fall outside expected ranges, the ECU stores a DTC and illuminates the check engine light.
  • Freeze frame data: When a code is set, the ECU also records engine conditions at that moment. This data helps pinpoint the exact cause.
  • Pending vs. confirmed: A code becomes "confirmed" after multiple drive cycles with the same fault. Pending codes may clear on their own.

Tools You'll Need for Diagnosis

  • OBD-II scanner — Essential for reading and clearing codes. A basic scanner works for most codes.
  • Digital multimeter — For testing sensor voltages, resistance, and continuity.
  • Repair manual — Vehicle-specific wiring diagrams and specifications.
  • Safety equipment — Gloves, safety glasses, jack stands for under-vehicle work.

When to See a Mechanic

While many security codes can be diagnosed at home, see a professional if:

  • The code is critical severity — driving may cause further damage
  • Multiple related codes are present — suggests a deeper systemic issue
  • You don't have the tools or experience for the required diagnostic steps
  • The repair involves fuel system, exhaust, or catalytic converter work