Code Definition

C1721 — Air Suspension Height Sensor Power Circuit Open

System: Chassis  |  Type: Manufacturer-Specific  |  Make: Ford

About C1721

C1721 is a manufacturer-specific chassis diagnostic trouble code recorded for Ford vehicles. It belongs to the C-prefix family of codes, which covers chassis, braking, steering, suspension, or stability-control faults.

When C1721 is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: Chassis (C) codes are stored in the ABS, traction control, or stability-control modules. An enhanced or OEM-level scan tool is usually required to read and clear them.

C1721 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

DTC C1721 relates to the air suspension ride height sensor power supply circuit. The air suspension control module provides a regulated voltage feed to the ride height sensors, which measure the distance between the chassis and the suspension so the module can maintain correct vehicle height by filling or venting the air springs. This code sets when the module detects an open circuit in the power feed to a height sensor, meaning the expected supply voltage is missing or the return path is broken. When C1721 is set, the module typically suspends automatic ride height control, a check air suspen...

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