Adaptive cruise control problem

[BlueSlateEX]

Yesterday I took a 2 hour road trip. I was using the adaptive cruise control on the highway going about 69 mph. After about an hour with no problems, cruising along fine, I heard a beep and all of a sudden my EX started slowing down. At first I thought it was sensing something a head of me, but there were no cars within the distance where it would slow me down. Then I noticed that set speed was turned off. I tried to reset the speed to 69, but it would just flash at me and not set. So, I turned it totally off. After about 10 minutes, I turned it back on and it worked fine. Then about 30 minutes later it did the same thing, beeped, turned off the set speed and wouldn't let me reset it until it had been turned completely off for at least 5 minutes. Has anybody else experienced this?

[Ace2cool]

I'm just spitballing here, but is your front bumper dirty/covered with bugs/dirt/mud ect? I know the adaptive cruise control works by using a forward emitting radar to sense vehicles in front of you and automatically slow down when it detects danger, so maybe the radar antenna is dirty, and is not getting a good signal/is getting too much feedback. The unit is usually behind the grille of most vehicles that are equipped, so I would check there. If not, you would probably have sensors on the bumper itself. Try cleaning the sensors.

[sg77]

Or was bright sunlight shining on the front of the car (interfering with the sensor)?

The owner's manual (pages 5-37 and 5-38 for my 2008 EX) lists some other possibilities:

----------------------
A chime sounds under the following conditions and the control is automatically canceled.
- When the vehicle speed falls below approximately 20 MPH (32 km/h)
- When the selector lever is shifted to the N (Neutral) position
- When the windshield wipers are operated at low speed (LO) or high speed (HI)
- When the VDC is turned off
- When the VDC operates
- When the engine coolant temperature becomes excessively high

...
- When a tire slips
- When the SNOW mode switch is turned on
- When strong light (sunlight, etc.) is directly shining on the front of the vehicle
...
- When the sensor window is dirty, making it impossible to detect a vehicle ahead, the ICC system is automatically canceled.
The chime sounds and the system warning light (Orange) will come on and the "CLEAN SENSOR" indicator will appear.
...
- When the ICC system is not operating properly, the chime sounds and the system warning light (Orange) will come on.

[EXceptional]

sg77... that's an excellent Post ! Good find.

[mad-ex]

If you have snow covering up the sensor in the front, it will disengage.

I have this issue when driving in a snow "storm" as well. Just make sure to clear off the rectangular sensor in the front and all should be fine.

[gofast24]

My 03 FX35 did the same thing. I acutally pulled off the free way, stoped the engine, re started and it worked again for 20-30 minutes. A module was replaced under warranty which fixed the problem.

[BlueSlateEX]

Thanks for the replies. Not sure what was going on. The sensors were clean, no snow, it was raining at the time, no sun. I did have the windshield wipers on, intermittant. Guess I will keep an eye on it and see if it happens again.

[Real10]

Your Adaptive cruise will turn off when you drive against direct sun light.

[SteveTheTech]

it was raining at the time, no sun. I did have the windshield wipers on, intermittant.

There ya go.

Ace2cool and SG77 you guys rock! That's dead on.

The Clean sensor thing is the only thing that is news to me. I have never seen that.