Lane Keep Assist System Malfunction (with UGN)

Diagnostic Instructions Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provides an overview of each diagnostic category. Diagnostic Fault Information

Circuit Number	Circuit Function	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performan
3153	Signal	1	1	—	—
3152	Control	2	2	3	—
1851	Ground	—	1, 2	—	—
1. Lane keep assist cannot be disabled or enable with the lane keep assist switch 2. Lane keep assist indicator inoperative 3. Lane keep assist indicator always on

Scan Tool Data Lane Departure Warning Switch Status

Control Module	Data List	Values	Normal Operation
K9 Body Control Module	Indicator Data	On/Off/Malfunction	The parameter will be Off when the lane keep assist switch is released/open and On when the lane keep assist switch is pressed/closed.

Circuit/System Description For an overview of the lane keep assist system, refer to Lane Keep Assist Description and Operation. Diagnostic Aids 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 situation. 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. Reference Information Schematic Reference Driver Assistance Systems Schematics Connector End View Reference Master Electrical Component List Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References Circuit/System Verification

Ignition ON.
Verify there are no DTCs set related to the forward collision alert or lane keep assist system ⇒ If any DTC’s are set Refer to Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If no DTC’s are set
Verify the B174W Front View Camera - Windshield is properly installed. Refer to Diagnostic Aids for details about identifying a properly installed B174W Front View Camera - Windshield. ⇒ If the B174W Front View Camera - Windshield is not properly installed Repair as necessary ⇓ If the B174W Front View Camera - Windshield is properly installed
Verify the are on the windshield in front of the B174W Front View Camera - Windshield is not blocked. Refer to Diagnostic Aids for details about identifying a blocked B174W Front View Camera - Windshield. ⇒ If the windshield is blocked Repair as necessary ⇓ If the windshield is not blocked
Verify the scan tool Lane Departure Warning Switch Status parameter is Off. ⇒ If the parameter is not Off Refer to Circuit/System Testing – Test 1. ⇓ If the parameter is Off
Verify the scan tool Lane Departure Warning Switch Status parameter is On while pressing the lane keep assist switch. ⇒ If the parameter is not On Refer to Circuit/System Testing – Test 1. ⇓ If the parameter is On
Press and release the lane keep assist switch. Verify the lane keep assist indicator on the lane keep assist switch turns on and off with each button press. ⇒ If the indicator does not turn on and off Refer to Circuit/System Testing – Test 2. ⇓ If the indicator turns on and off
Drive the vehicle at speed greater than 37 mph (60 km/h) in good weather conditions on a road with good lane markings. Verify the green lake keep assist indicator illuminated on the P16 Instrument Panel Cluster Control Module Control Module and the lane keep assist system is functioning properly. ⇒ If the lane keep assist system does not function Refer to Diagnostic Aids to identify conditions that can cause the lane keep assist system to become inoperative and diagnose these systems as necessary. ⇓ If the lane keep assist system functions as normal
All OK. A fault is currently not present and may be an intermittent condition. Refer to Diagnostic Aids. It may be helpful to discuss with the customer the conditions present when the concern occurred, as it might be a normal system response to the driving environment or road conditions. Circuit/System Testing Test 1
Ignition OFF, disconnect the connector at the S48C Multifunction Switch 1 - Instrument Panel.
Verify a test lamp illuminates between ground circuit terminal 10 and B+ ⇒ If the test lamp does not illuminate Repair the open/high resistance on circuit 1851 or the ground connection. ⇓ If the test lamp illuminates
Ignition ON.
Verify the scan tool Lane Departure Warning Switch Status parameter is Off. ⇒ If the parameter is not Off 4.1. Test circuit 3153 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found 4.2. Replace the K9 Body Control Module. ⇓ If the parameter is Off
Connect a 3 A fused jumper wire between signal circuit terminal 4 and ground.
Verify the scan tool Lane Departure Warning Switch Status parameter is On. ⇒ If the parameter is not On 6.1. Test circuit 3153 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If a short to ground is not found 6.2. Replace the K9 Body Control Module. ⇓ If the parameter is On
Replace the S48C Multifunction Switch 1 - Instrument Panel. Test 2
Ignition OFF, disconnect the X3 connector at the K9 Body Control Module, ignition ON.
Verify the lane keep assist indicator is not illuminated. ⇒ If the indicator is illuminated 2.1. Test circuit 3152 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found 2.2. Replace the S48C Multifunction Switch 1 - Instrument Panel. ⇓ If the indicator is not illuminated
Connect a 3 A fused jumper wire between control circuit terminal 5 and B+.
Verify the lane keep assist indicator is illuminated. ⇓ If the indicator is not illuminated 4.1. Test circuit 1851 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit or the ground connection. ⇓ If an open/high resistance is not found 4.2. Test circuit 3152 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 4.3. Test circuit 3152 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 4.4. Replace the S48C Multifunction Switch 1 - Instrument Panel. ⇒ If the indicator is illuminated
Replace the K9 Body Control Module. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Driver Assistance Systems Component Replacement Reference Control Module References for control module replacement, programming, and setup