C1990 on Ford: How to Diagnose & Fix
Forward Collision Warning System Fault
1 Ford model · 1 documented issue · $300-$1,500 repair
C1990 on Ford by model: symptoms, diagnosis and fix
The 2003-2017 Ford Expedition with optional air suspension (standard on Eddie Bauer, King Ranch, Platinum, and EL/MAX trims) suffers from air suspension compressor failure, air spring leaks, and ride height sensor malfunctions. The compressor, located under the vehicle, is exposed to road debris, salt, and moisture which degrades the motor and valves. When air springs develop leaks, the compressor runs continuously trying to maintain ride height, leading to premature burnout. RepairPal estimates compressor replacement between $666 and $724, though dealer pricing can reach $1,200. NHTSA has received hundreds of complaints regarding air suspension failures. Strutmasters.com notes that 2007-2011 Expedition and Navigator share the same air suspension system and failure patterns. Many owners opt for air-to-coil spring conversion kits as a permanent, lower-cost solution.
Common Symptoms
- Rear of vehicle sagging or sitting noticeably lower
- Air suspension warning light or message on dash
- Compressor runs excessively or continuously
- Loud compressor noise from under the vehicle
- Harsh ride over bumps
- Vehicle leans to one side
- Hissing sound from air springs or compressor
- Vehicle bottoming out on speed bumps or driveway transitions
How to Fix
Most cost-effective permanent fix is an air-to-coil spring conversion kit from Strutmasters or Arnott ($300-500 for kit plus installation). If keeping air suspension: replace the compressor (Arnott P-2936 or Dorman 949-200, $200-400 part), both rear air springs ($150-250 each), and inspect all air lines for cracks. Always replace air springs in pairs. Compressor relay should also be checked - a corroded relay causes intermittent compressor operation. RepairPal estimates $666-724 for compressor replacement at a shop.
Sources for this issue (1)
C1990 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does C1990 mean on a Ford?
C1990 stands for "Forward Collision Warning System Fault." C1990 is a safety-system code indicating a fault in the Forward Collision Warning (FCW) system, which uses a front-facing camera and/or radar to watch for vehicles or obstacles ahead and alert you to a potential crash. The module sets this code when it loses confidence in the system's ability to detect threats reliably, often because a sensor is blocked, misaligned, miscommunicating, or reporting a fault. It generally means the collision-warning (and often automatic emergency braking) features are disabled until repaired. The car still drives normally, but the safety alert function is offline. On Ford it is documented across 1 model: Expedition.
What are the most common causes of C1990?
The most common causes of C1990 are: Obstructed radar or camera (ice, snow, mud, dirt, bug debris, sticker), Misaligned front radar sensor or windshield camera after impact or service, Faulty forward-facing camera or radar module, Damaged or corroded wiring/connector to the FCW sensor, Communication (CAN bus) fault between the FCW module and other systems, Low battery voltage or charging-system problem, Windshield replacement without proper camera recalibration, Front bumper or grille damage affecting radar aim. The specific cause varies by vehicle.
How much does it cost to fix C1990 on a Ford?
Published repair estimates on Ford range from $300 to $1,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for C1990 on a different make?
View C1990 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.