C1726 on 2003-2017 Ford Expedition — Steering Torque Sensor Signal Invalid
1 vehicles · 1 makes · $200-$1,500 repair
How to diagnose and fix C1726: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Ford Expedition · 2003–2017
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)
Ford Expedition · 2003–2025
Expeditions equipped with the rear air suspension system experience compressor failure, causing the rear of the vehicle to sag. The compressor wears out from overwork — it cycles frequently due to slow air leaks in the air springs (bags) and supply lines. When the compressor fails, the rear drops to the bump stops, creating a nose-up stance and poor ride quality. The air springs themselves develop dry rot cracks and leak, particularly in dry or hot climates.
Common Symptoms
- Rear of vehicle sagging or sitting low
- Compressor runs constantly or makes loud noise
- Suspension warning message on dashboard
- Rear bounces excessively over bumps
- Vehicle leans to one side in rear
How to Fix
Replace the air suspension compressor ($150-300 for aftermarket, $200-400 OEM). Simultaneously inspect and replace any leaking air springs ($100-200 each, two required). Total repair to restore the air system: $500-1,200. Many owners convert to conventional coil springs using a conversion kit ($200-400) from Strutmasters or Arnott, which eliminates the air system entirely and requires no future maintenance.
Sources for this issue (1)
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C1726 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 C1726 mean?
C1726 stands for "Steering Torque Sensor Signal Invalid." C1726 is a steering/chassis code indicating the steering torque sensor is sending an invalid or implausible signal. On electric power steering (EPS) systems, the torque sensor measures how hard you're turning the wheel so the system knows how much assist to provide. When the EPS module receives a signal that's out of range, erratic, or doesn't agree with its internal checks, it flags the data as invalid. It generally results in reduced or lost power-steering assist (heavier steering), with a steering or EPS warning light, even though the car remains steerable.
What are the most common causes of C1726?
The most common causes of C1726 are: Faulty steering torque sensor, Wiring or connector fault in the torque sensor circuit, Loss of or unstable sensor reference/supply voltage, Corrosion or moisture in the steering column connectors, Torque sensor not calibrated/initialized after service, Internal EPS module fault, Low battery voltage affecting sensor operation. The specific cause varies by vehicle.
How much does it cost to fix C1726?
Repair costs for C1726 range from $200 to $1,500, depending on the vehicle and root cause.
Which vehicles are affected by C1726?
Au7o has documented C1726 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.