C1979 on 2004-2024 Ford F-150 — IWE Solenoid Circuit Failure
1 vehicles · 1 makes · $100-$700 repair
Most Reported On
C1979 is an OBD-II diagnostic trouble code meaning “IWE Solenoid Circuit Failure.” A Ford chassis code covering the Integrated Wheel End (IWE) vacuum solenoid circuit, used on 4WD F-150, Expedition and Navigator. The IWE system uses engine vacuum to lock and unlock the front hubs; the 4WD control module monitors the IWE solenoid and sets C1979 when the circuit is not within specification. Typical symptoms are a grinding or clicking noise from the front hubs (especially on acceleration or turns), a 4WD light or non-functioning 4WD selector, and front hubs that will not lock or unlock properly. Continuing to drive with partially engaged hubs can damage the wheel-end actuators. This code is most commonly reported on 2004-2024 Ford F-150, with repair costs ranging from $100 to $700.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
C1979 does not use the standard P/B/C/U prefix. It may be a manufacturer-specific code, so verify that a scanner supports your exact year, model and module before buying.
FAQ
What does C1979 mean?
C1979 stands for "IWE Solenoid Circuit Failure." A Ford chassis code covering the Integrated Wheel End (IWE) vacuum solenoid circuit, used on 4WD F-150, Expedition and Navigator. The IWE system uses engine vacuum to lock and unlock the front hubs; the 4WD control module monitors the IWE solenoid and sets C1979 when the circuit is not within specification. Typical symptoms are a grinding or clicking noise from the front hubs (especially on acceleration or turns), a 4WD light or non-functioning 4WD selector, and front hubs that will not lock or unlock properly. Continuing to drive with partially engaged hubs can damage the wheel-end actuators.
What are the most common causes of C1979?
The most common causes of C1979 are: Failed IWE vacuum solenoid, Damaged, chafed, or corroded IWE solenoid wiring and connector, Cracked or collapsed vacuum lines to the front hubs (very common on F-150), Leaking vacuum reservoir or check valve, Failed IWE hub actuators, 4WD/transfer case control module fault. The specific cause varies by vehicle.
How much does it cost to fix C1979?
Repair costs for C1979 range from $100 to $700, depending on the vehicle and root cause.
Which vehicles are affected by C1979?
Au7o has documented C1979 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.