Chassis, generic

C0604 Active Air Dam Control Circuit Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

C0604 is the air dam code that makers really publish: the panel does not reach or hold its commanded position even though the circuit itself looks sound. Ford stores C0604:00 in the PCM of 2021–2023 F-150s, often with a cluster warning that the air dam system has failed; its fixes are new left and right actuators for an actuator firmware issue (SSM 51718), a PCM reflash (TSB 24-2404, later 25-2155 and 25-2236) and, on 2021–2025 trucks, new bolts where the actuator-to-dam bolts broke (SSM 54705). Stellantis ties C0604 to water in the connector and to fascia contact causing a clunk at 15–35 mph, and on a 2025 Ram 1500 to impact damage, with the MIL lit. GM's patent splits such faults into sensor, actuator and panel cases.

Likely causes

Actuator firmware or PCM software level with known false or real faults (Ford F-150)
Broken bolts between actuator and air dam, panel hangs
Air dam bent, cracked or jammed after ground contact or debris
Water or corrosion in the actuator connector
Air dam lip rubbing on the front fascia

Symptoms

  • Active Air Dam System Fault See Manual message
  • Air dam hangs down or does not retract
  • Clunk from the front end when driving at moderate speed or decelerating
  • Check engine lamp on some Ram trucks

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–900
Time0.3–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

active air dam actuatoractive air dam modulepowertrain control module

Related codes

C0601C0602C0603C0630U0645

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.