neuronbob

This information comes from the August Acura Service Bulletin that came out before Labor Day. I thought it might be useful. The full information with pictures is in the Acura Service Bulletin thread that is a sticky at the top of the forum.

Automatic Headlight Aiming Explained

Currently Applies To: ’07–09 MDX with Sport Package and ’05–09 RL

Some Acura models feature automatic aiming of the low beam headlights. There are two aiming systems that do
this: the simpler headlight leveling system and the more complex adaptive front lighting system (AFS). The
headlight leveling system keeps the headlights in proper vertical adjustment to compensate for changes in the
vehicle’s ride height. The AFS includes the headlight leveling system plus swivel control to move the headlights left
and right in response to steering wheel inputs during cornering and turning.
To help boost your product knowledge, here’s a brief explanation of how each of these systems work, based on
model and trim level:

RL: This model uses the headlight leveling system, consisting of the headlight leveling control unit, the
suspension stroke sensor, and the left and right headlight leveling motors. The suspension stroke sensor
monitors the vehicle’s ride height every 3 minutes while the vehicle is moving with the headlights on, and
8 seconds after it stops with the ignition switch and the headlights on. If the control unit detects a change in
ride height, it controls the headlight leveling motors to keep the headlights in proper vertical adjustment. The
headlight leveling system has no self-diagnostic function.
To troubleshoot and repair, check out pages 22-278 thru 22-286 of the ’05–08 RL S/M. (Online, enter keywords
HEADLIGHT LEVELING and select from the list.)

RL with Technology Package: This model uses the AFS, consisting of the adaptive front lighting control unit,
the suspension stroke sensor, the steering angle sensor, the headlight leveling motors, the adaptive front
lighting gearboxes, the AFS indicator, and the AFS OFF switch. The AFS uses the headlight leveling motors to
aim the headlights up and down and the adaptive front lighting gearboxes to aim them left and right, depending
on the steering angle sensor input. The AFS control unit has a self-diagnostic function with its own set of DTCs
and a fail-safe function. If there’s a problem in any of the sensors, the B-CAN system, or the control unit, the
AFS goes into fail-safe mode. The system stops control and the AFS indicator blinks to show the problem. If
the problem is with the swivel control, the headlight aiming stays centered. If it’s with the leveling control, the
headlight aiming stays at 0.6 degree under its current position. To troubleshoot and repair the AFS, check out
pages 22-231 thru 22-277 of the ’05–08 RL S/M. (Online, enter keyword AFS and select rom the list.)

rlerman

Thanks for the post. I have had a diagnostic message warning about the possibility that my AFS may not be working. I've had my rl into Acura to be checked and they said they system is working fine, but they didn't know how to clear the message. Any idea how to clear it.

BTW, I know the system works because I can see the lights swiveling, particularly when I pull up to my garage and put it in park.

dlynch

Thanks for the post. Great catch. Great forum!
DaveL

Chas2

It is interesting that Acura did not distinguish between which cars had the Technology package as standard. In my book, that would be all 2005 and 2006 RLs. Only in 2007 did they start making the distinction, and only starting in that year, did they have RLs without AFS, i.e., the base model.

static808

Thanks. My '05 RL has had the AFS message going off every day for like two weeks. Was finally going to setup an appointment when, it stopped. Very weird. I have over 60K on the car but have extended warranty so I'll take it in and tell them about this bulletin.