Adaptive Cruise Control (ACC) Symptom Troubleshooting - Intermittently senses the vehicle driving ahead

1.

Road condition check:

Road condition check

?1.	Find out if the detection problem occurs only on a particular road such as a winding road, an entrance of a corner, an exit of a corner, a tight corner, or a bad road.

Does it occur only on a particular road?


	YES

Explain to the customer that the system sometimes cannot detect under certain road conditions.?


	NO

Go to step 2.

2.

Weather condition check:

Weather condition check

?1.	Find out if the detection problem occurs only under poor weather conditions such as fog, snow, heavy rain, or gusty winds.

Does it occur only under poor weather conditions?


	YES

Explain to the customer that the system sometimes cannot detect under poor weather conditions.?


	NO

Go to step 3.

3.

Driving condition check:

Driving condition check

?1.

Find out if the detection problem occurs only when the vehicle ahead drives under these conditions:

	Merged into the lane suddenly.
	Closing on a vehicle within 4 m (13 ft).

Does it occur only under certain driving conditions?


	YES

Explain to the customer that the system sometimes cannot detect under certain driving conditions.?


	NO

Go to step 4.

4.

Millimeter wave radar aiming check:

Millimeter wave radar aiming check

?1.	Confirm if the radar detects vehicles driving in another lane.

Does it detect vehicles in other lanes?


	YES

The millimeter wave radar horizontal aiming is incorrect. Aim the millimeter wave radar.?


	NO

Go to step 5.

5.

All condition check:

All condition check

?1.	Find out if the detection problem occurs under all conditions.

Does it occur under all conditions?


	YES

The millimeter wave radar vertical aiming is incorrect. Aim the millimeter wave radar.?


	NO

Go to step 6.

6.

Other component check:

Other component check

?1.

Confirm if the detection problem is caused by instability.

NOTE: If the cause of the misdetection or undetectable problems is unclear, it is possible that the problem was caused by environmental conditions. Explain to the customer that intermittent failures are sometimes caused by environmental conditions.

Is the vehicle unstable? (Compare it to a known-good, like vehicle.)


	YES

Check other components such as VSA modulator-control unit or wheel speed sensors, etc.?


	NO

Go to step 7.

7.

Heavy load check:

Heavy load check

?1.	Check if there was a heavy load in the trunk.

Was there a heavy load in the trunk?


	YES

Remove the heavy load from the trunk. Advise the customer that this problem may occur temporarily when hauling heavy loads.?


	NO

Go to step 8.

8.

Millimeter wave radar visual check:

Millimeter wave radar visual check

?1.	Check for dirt, dust, or snow on the surface of the millimeter wave radar.

Are the millimeter wave radar OK?


	YES

Go to step 9.


	NO

Clean the millimeter wave radar.?

9.

Vehicle's history check:

Vehicle's history check

?1.	Check the vehicle's history for front end collision repairs.

Has the vehicle been in a collision and repaired?


	YES

Go to step 10.


	NO

Go to step 12.

10.

Millimeter wave radar installation check:

Millimeter wave radar installation check

?1.	Check if the millimeter wave radar assembly is installed correctly, and also check if the vehicle frame is straight.

Are all parts installed correctly?


	YES

Go to step 11.


	NO

Reinstall the part correctly, or if damaged, replace the part, then aim the millimeter wave radar.?

11.

Vehicle ride height check:

Vehicle ride height check

?1.	Measure the front and rear vehicle ride height.

Is the vehicle ride height equal?


	YES

Go to step 12.


	NO

Inspect the suspension for damage, and compare ride height to a known-good vehicle. Adjust the wheel alignment as needed.?

12.

Wheel alignment check:

Wheel alignment check

?1.	Check the wheel alignment.

Is the wheel alignment OK?


	YES

Aim the millimeter wave radar.?


	NO

Adjust the wheel alignment.?