C1991: Lane Departure Warning System Fault
1 vehicles · 1 makes · $300-$1,500 repair
C1991 is an OBD-II diagnostic trouble code meaning “Lane Departure Warning System Fault.” The lane departure warning/lane keeping assist system has a fault. This code appears across 1 vehicle models from 1 manufacturers, with repair costs ranging from $300 to $1,500.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose C1991, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
Vehicles Affected (1)
FAQ
What does C1991 mean?
C1991 stands for "Lane Departure Warning System Fault." The lane departure warning/lane keeping assist system has a fault.
What are the most common causes of C1991?
The most common causes of C1991 are: Camera obstruction (dirty windshield), Camera calibration needed, After windshield replacement, Camera module fault, Poor lane markings. The specific cause varies by vehicle.
How much does it cost to fix C1991?
Repair costs for C1991 range from $300 to $1,500, depending on the vehicle and root cause.
Which vehicles are affected by C1991?
Au7o has documented C1991 across 1 vehicle models from 1 manufacturers: Ford.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.