B1799 – Lamp Turn Signal Front Output Circuit Open: Symptoms, Causes, Diagnosis & Repair Cost (2026 Guide)

B1799

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Overview

The control module stored B1799 because it detected a problem with: Lamp Turn Signal Front Output Circuit Open.

B1799 relates to Lamp Turn Signal Front Output Circuit Open. Use a quality scan tool, follow wiring diagrams for your vehicle, and confirm tests before replacing expensive parts.

What does the B1799 code mean?

When B1799 is set, the vehicle’s diagnostics detected an issue described as: Lamp Turn Signal Front Output Circuit Open. In practice, the ECM/PCM (and related modules) compare sensor inputs, commanded outputs, and self-tests for that subsystem. The exact repair depends on whether the fault is wiring-related, component-related, or a rationality/performance issue for this circuit or system.

Common symptoms of B1799

  • Intermittent warning chime
  • Safety system disabled message
  • Passenger sensor messages
  • SRS/airbag warning lamp
  • Seat belt warning issues
  • Scan tool shows restraint codes

Possible causes

  • Fault affecting Lamp Turn Signal Front Output Circuit Open (wiring, connector, or component)
  • Component failure in the described system
  • Electrical fault in the monitored circuit
  • Control module strategy or calibration issue
  • Control module or software calibration issue (less common—verify tests first)
  • Past repairs or aftermarket parts causing out-of-spec operation

How to diagnose B1799

  1. Scan for B1799 and review freeze frame / pending codes for related faults
  2. Inspect connectors and wiring related to: Lamp Turn Signal Front Output Circuit Open
  3. Compare live data and commanded vs actual values for the affected system (per service information)
  4. Perform circuit tests appropriate to the fault type (continuity, voltage, resistance) before replacing parts
  5. Confirm power and ground integrity at the relevant module or sensor
  6. After repair, clear DTCs and verify under the conditions that originally set B1799

Tip: Use a scan tool that shows live data and freeze frame for the conditions when the code set.

Severity of code B1799

High: This fault can impact safety-related systems or core drivability—prioritize professional diagnosis.

Can you drive with B1799?

Short trips may be okay if the vehicle feels normal, but have it diagnosed—especially if performance, safety warnings, or overheating are present.

Avoid heavy acceleration, towing, or long highway drives until the cause of B1799 is confirmed and repaired.

How to fix it (step-by-step)

  1. Start with visual inspection and connector cleaning/tightening where needed
  2. Confirm failure mode with testing—avoid swapping parts without evidence
  3. Repair wiring or replace the failed component per manufacturer procedure
  4. Clear faults, run relearns if required, and road test to confirm

Repair & fix options

  • Clear codes and verify with drive cycle
  • Test component against service limits
  • Inspect connectors and wiring first
  • Clear codes and verify repair with a drive cycle and readiness where applicable
  • Reinspect related monitors if the code returns after repair

Typical repair cost

$120 – $1,800+ for many common repairs

Estimated cost breakdown for B1799
Repair type Typical range
Diagnostic And Minor $120 – $600
Common Component Work $200 – $900
Major Subsystem Repair $400 – $1,800+
Severe Or Replacement Varies widely—see a qualified shop

How to help prevent B1799 in the future

  • Fix new codes early before secondary damage or catalyst stress
  • Keep connectors clean and secure; address rodent or water intrusion in harnesses
  • Use the correct fluids/parts for your vehicle and service intervals
  • Avoid ignoring pending codes after battery work or repairs

When to see a mechanic

Schedule diagnosis if the check engine light is on, drivability is worse, or you notice new noises, smells, or warning lamps. For safety-related (SRS/ABS) or overheating symptoms, prioritize a qualified shop immediately.

Common mistakes when diagnosing B1799

  • Replacing sensors/modules without verifying wiring and reference voltages
  • Ignoring related codes that identify the real root cause
  • Clearing codes without a verification drive cycle

Common vehicles & notes for B1799

  • Nissan / Hyundai models (common examples—verify for your vehicle)
  • Kia / Mazda applications vary by engine and model year
  • Many other makes—this is a standardized OBD-II definition: Lamp Turn Signal Front Output Circuit Open

B1799 is reported across many platforms including Nissan, Hyundai, Kia, Mazda. Always use VIN-specific service information for testing limits and calibration steps.

Frequently asked questions

What does B1799 mean?

B1799 indicates a fault involving Lamp Turn Signal Front Output Circuit Open, based on what the control module detected during self-tests or live monitoring.

Is it safe to drive with B1799?

If the vehicle runs normally and no warning lights are flashing, short trips may be reasonable—but avoid ignoring symptoms like misfire, overheating, ABS/SRS warnings, or major loss of power.

How much does it cost to fix B1799?

Typical repairs often fall in the ranges shown on this page, but final cost depends on labor rate, parts quality, and whether the issue is wiring vs. a major component.

What is the most common cause of B1799?

Most shops start with wiring/connectors and the directly monitored component for “Lamp Turn Signal Front Output Circuit Open,” then expand testing if the fault returns.

Will B1799 clear itself?

It may become intermittent, but if the underlying fault remains, the code will usually return—especially after a drive cycle.

Can a weak battery cause B1799?

Low system voltage can cause odd sensor/module behavior, but you should still validate the actual DTC and perform normal circuit/component tests.

Related tools

This information is for educational purposes only and is not a substitute for hands-on diagnosis. Always follow manufacturer service information and consult a qualified automotive technician for repairs.