Diagnostic Test

WARNING: This page is about a different car, the 2010 Dodge Charger and 2010 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

VERIFY DTC IS ACTIVE
NOTE: To help in the service of the ACC System, it is recommended speaking to the customer to find out what type of environment they were driving in when the cruise concern took place. Heavy rain, snow, ice, and fog can cause the ACC system to become unavailable. This should be considered normal operation and no repair is necessary.

NOTE: Vehicles that have had the suspension modified and/or a aftermarket grill installed that blocks the ACC sensor can cause the ACC system not to operate properly.
1. Using a scan tool, read ACC DTCs.
  Is the DTC active at this time?
  
  Yes
  - Go to step 2
  No
  - No repair is necessary. Make sure the lens is free of dirt, damage, and other obstructions. Clear the DTC and verify proper operation of the ACC system.
CHECK ACC SENSOR LENS
NOTE: Make sure the ACC Sensor lens is free from dirt and debris (mud, dirt, ice, road debris) that would compromise the function of the ACC system.
1. Perform a thorough visual and physical inspect of the ACC Module, look for a missing sensor lens or a damaged lens.
  Is the lens damaged or missing?
  
  Yes
  - Replace the ACC Module in accordance with the Service Information.
  - Perform the ACC MODULE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Adaptive Cruise Control (ACC) - Standard Procedure .
  No
  - Check the ACC Module harness connector terminals for corrosion, damage, or terminal push out. Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits. Repair as necessary. If the connector and wiring are found to be OK, replace the ACC Module in accordance with the service information.
  - Perform the ACC MODULE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Adaptive Cruise Control (ACC) - Standard Procedure .