2024-2025 Jeep/Dodge ACC/FCW Unavailable Service Required TSB

Owners of 2024-2025 Jeep Compass and Dodge Durango vehicles may encounter dashboard messages such as "ACC/FCW Unavailable Service Required" or "Adaptive Cruise Control (ACC) System is Disabled". These messages often coincide with the Adaptive Cruise Control and other driver assist features becoming inoperative. This issue, which can lead to a Jeep Compass ACC FCW unavailable state, is addressed by Stellantis Technical Service Bulletin (TSB) S2508000013, released in February 2025.

This TSB provides guidance for technicians to diagnose and resolve the underlying causes of these warnings, particularly when the Diagnostic Trouble Code (DTC) P1666-00 is present. It emphasizes a thorough diagnostic approach before replacing major components.

Symptoms

If your 2024-2025 Jeep Compass or Dodge Durango is affected, you might observe the following on your vehicle's cluster Electronic Vehicle Information Center (EVIC):

• A warning message stating: "ACC/FCW Unavailable Service Required"
• A notification indicating: "Adaptive Cruise Control (ACC) System is Disabled"
• The Driver Assist system may be inoperative.

These symptoms collectively point to a problem with the vehicle's advanced driver-assistance systems, leading to a Jeep Compass ACC FCW unavailable condition.

Fault Codes / DTCs

Technicians may observe one or more of the following Diagnostic Trouble Codes (DTCs) when diagnosing the "ACC/FCW Unavailable Service Required" issue:

Code	Description
P1666-00	CRUISE CONTROL MODULE INTERNAL (MODULE, Adaptive Cruise Control (ACC))
C212A-84	System Below Allowable Range (Battery related)
B21DD-16	System Voltage-Circuit Voltage Below Threshold (Battery related)
B21DD-84	System Voltage-Signal Below Allowable Range (Battery related)
C14A4-00	Sensor Adjustment Required (Mechanical related)
C0063-9A	Yaw Rate Sensor-Component or System Operating Conditions

Diagnosis and Trigger Conditions

DTC P1666-00 is a general diagnostic trouble code that can appear alongside other DTCs, potentially affecting the functionality of the Driver Assistance System Module (DASM). It is crucial to begin the diagnostic process by addressing any DTCs that are currently in an "Active" status.

Important Note: The Driver Assistance System Module (DASM) should not be replaced if DTC P1666-00 is found to be in a "Stored" status. Instead, technicians should investigate specific conditions that might cause P1666-00 to be stored.

Conditions to check if P1666-00 is in a "Stored" status include:

Battery Condition

Ensure the vehicle's battery State of Charge (SOC) is above 85%. The battery should also be charged to a nominal voltage range of 10-16 Volts. Technicians should check for any voltage-related DTCs, such as C212A-84, B21DD-16, B21DD-84, or any indications of undervoltage or overvoltage.

Electrical/Wiring Harness Integrity

Inspect the wiring harness for any signs of corrosion, tears, or damage. Pay close attention to areas related to the fascia, the Steering Column Control Module (SCCM), or the Anti-lock Braking System (ABS), as these can impact the Adaptive Cruise Control (ACC) system's operation and contribute to the Jeep Compass ACC FCW unavailable warning.

Mechanical Inspection

In some instances, P1666-00 may be set in conjunction with DTC C14A4-00, which indicates a sensor adjustment is required. A broken tab on the DASM can also trigger this DTC. Technicians should thoroughly inspect the DASM to ensure there is no damage to its bracket or mounting tabs. For further guidance on mechanical inspections, refer to TSB S2408000114.

Yaw Rate Sensor

If DTC C0063-9A (Yaw Rate Sensor-Component or System Operating Conditions) is present along with P1666-00, the ignition should be cycled. This action typically moves any active DTCs to a stored status if no underlying issues are present. If an active DTC persists, ensure all other conditions related to P1666-00 have been resolved before continuing with standard DTC diagnostics for the yaw rate sensor.

Important Warnings

Owners and technicians should be aware of the following disclaimers from Stellantis regarding this communication:

• "This document does not authorize warranty repairs."
• "This communication documents a record of past experiences. STAR Online does not provide any conclusions about what is wrong with the vehicle. Rather, it captures all previous cases known that appear to be similar or related to the vehicle symptom / condition. You are the expert, and you are responsible for deciding on the appropriate course of action."

Source: NHTSA ID 11014137