Diagnostic Aids

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

The lane keep assist system operations in three general states:

Off: The system has been turned off by the driver using the lane keep assist switch. The lane keep assist indicator on the lane keep assist switch will not be illuminated.
Not Ready To Assist: The system is enabled and the lane keep assist indicator on the lane keep assist switch is illuminated, but the green lane keep assist indicator on the P16 Instrument Panel Cluster Control Module Control Module is not illuminated. This indicates the system not active and is not ready to assist. This occurs when any of the following conditions are present:
- Vehicle speed is less than 37 mph (60 km/h). The system is designed to function at speeds greater than 37 mph (60 km/h).
- The system cannot detect lane markings. This may be because there are no lane markings, as on a country road, or the lane markings cannot be determined due to snow, rain, or other driving conditions.
- The windshield area in front of the B174W Frontview Camera - Windshield is blocked by fog, dirt, damage to the windshield, or other elements that may prevent the camera from detecting lane markings.
Ready To Assist: The system is enabled and ready to warn of the unintentional lane crossing. The system is ready to assist when the green lane keep assist indicator is illuminated on the P16 Instrument Panel Cluster Control Module Control Module.

The B174W Front View Camera - Windshield may have trouble functioning under the following scenarios:

Dirty windshield glass or obstruction on windshield. This may included dirt, snow, or ice, a tinted windshield, windshield tint strips, or vinyl strips or graphics on the windshield. Additionally, other obstructions such as brush guards or hood deflectors may obstruct view of the B174W Frontview Camera - Windshield and hinder it's ability to identify objects, vehicles, and lane markings.
The B174W Frontview Camera - Windshield is not properly installed. Verify it is snapped into tabs and is secure. Ensure the bracket is in the correct location by comparing to a known good vehicle. This is especially important if the windshield was recently replaced. Some aftermarket windshield may have the B174W Frontview Camera - Windshield in the incorrect location. Improper installation of a replacement windshield may also prevent completion of the learn if the windshield was not centered and leveled in the vehicle's windshield opening.
Driving through snow or fog, or driving directly into the sun.
Driving on windy or hilly roads.

The lane keep assist system can be disengaged for a number of reasons. These reasons may be a normal function of the vehicle or as a result of action the driver has taken. They also may be because of a fault in a vehicle system. The K124 Image Processing Module has an available scan tool data list that can help identify what may have caused a lane keep assist disable scenatio. The scan tool Lane Keep Assist Disable History Data list identifies conditions that will cause a lane keep assist disable.

When attempting to diagnose the system, it is important to discuss with the customer the conditions under which the apparent malfunction occurred. This is critical to help identify those scenarios where the inhibit or disengage is the result of a driver action or normal system response and clarify how the function works. It is also critical to identify when the apparent malfunction occurred when attempting to replicate the condition. The parameters in the scan tool Lane Keep Assist Disable History Data list can be used to help isolate what is causing an inhibit or disengage condition. The scan tool Lane Keep Assist Disable History Data list has parameters that identify the last eight causes of an inhibit and the last eight causes of a disengage. For each Lane Keep Assist Disable History Data parameter, extra information is included in additional parameters: Odometer at First Malfunction, Odometer at Last Malfunction, Diagnostic Status, Malfunction Counter, and Ignition Cycles Since Last Diagnostic Event. The scan tool parameters are a rolling snapshot of the last eight inhibit and disengage reasons, however, if the same condition causes a disable, the reason will not be logged in the next parameter. Instead, the Malfunction Counter parameter will increment and the Odometer at Last Malfunction parameter will update with the most recent odometer value that the condition occurred. When diagnosing a disable concern, especially in the case of an intermittent condition, these parameters are useful in helping determine the cause. Recurring causes will have a larger number in the Malfunction Counter parameter and will likely have a wide variance between the Odometer at First Malfunction and Odometer at Last Malfunction value, indicating the condition has occurred over a period of time driving the vehicle.