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bought the car with ACC, braking guard and audi lane assist not working. with the regular message " ACC AND BRAKING GUARD UNAVAILABLE" i figured it was out of alignment and probably will need calibration... so finally made an appointment at the dealer and after keeping the car for whole week they are telling me that my front left sensor is bad.
i didnt pay for new sensor and decided to pick up the car now i have no errors on my cluster and surprisingly lane assist is working perfectly however the cruise control doesn't work like if its not even installed in the car i can press any button on the stalk and nothing .... before everytime i tried to use the cruise control or even lane assist it would tell me cruise control or lane assist unavailable.
does lane assist work using the camera mounted on the windshield only or does it also uses the 2 sensors that are located in the front bumper ? becoz if lane assist uses the radar sensors aswell then i doubt the sensor is bad and its just misalignment
the sensor is about 2000 with tax and i can probably buy it cheaper online new one or alot cheaper for a used one but i will need to pay for calibration again heres the fault code i am getting when i scanned my car again, dealer says the j450 module is sending signal but not receiving it
Lane assist uses a camera, behind the mirror I believe. The OEM part is cheapest here, if that's what you end needing. Interestingly, whether it's the right or left makes a fair difference in cost. As with anything electrical, inspecting the condition of the wires and connectors is always worth doing.
Adaptive cruise are the two outer sensors in the fog light position, at least with LED's like my S8. Likely the brake assist function too. Might be in mirror area for lane assist. Front visual camera for MMI parking and 360 display is in ring area with the rounded face. If night vision equipped, I think that is a large round flat sensor in another part of rings.
Backing up to OP, I saw this same issue on a 2015 S8 CPO I test drove locally. I went out to freeway with it--with no salesman on board --and eventually got to ACC and got that same error immediately. When I got back and started looking car over, I pushed on bumper and it seemed strangely loose. Then I saw majority of screws missing in fender area on both sides. At that point it was clear someone did a hack job on it, likely at auction yard (...it was perhaps washed through). Obviously explained the ACC error I saw too. Very disappointed that car was labeled CPO. The checklist would not have been worth the toilet paper the tech skipped while filling it out in the John with a brewski or two in hand. Needless to say, i was on my way to the one I eventually bought in the next 5 minutes.
Since they had the car for whole week they checked the ground and power and all other cables and found nothing wrong with them, the voltage reading is same for front left and right sensor i just dont want to buy the sensor and findout something else is an issue wondering if anyone else had same issue where error code was for misaligned sensor and needed to replace it or is the tech at the dealership just doesn't know what hea doing.
Also what did they do to deactivate the error message aswell as no response from the cruise control stalk ? Alot of my settings were changed like seatbelt warning and all is there anyway i can check in vcds if cruise control was deactivated?
Only other thing i can think of is if they left something unplugged
VCDS can tell you if it's been deactivated. You just need to check the appropriate module. It's odd that your stuff is shut off entirely. Makes me want to suggest a second dealer look at it. I tend to be quick to be suspicious of dealers, though. Feel free not to take their word for it on the wiring and connectors.
Text and illustration from the D4 intro SSP about ACC. Sensors in bumper; text explains where camera comes in.
Just know what Audi says there, other than you can find the configuration check box stuff when you go into module coding with VCDS. Someone could have played with that deeper in I suppose. Not good/right and perhaps fraud in connection w/ sale of a vehicle if that actually happened, but that's another discussion.
Now that I think about it, it would make sense that lane assist would be a visual detection (camera only) and the bumper sensors would not come into play. ACC would need to use both - radar and visual. I have both the camera and the sensors installed but my car does not have lane assist, only ACC.
4h0 907 541a is left sensor and dealer told me this one is BAD
4h0 907 561a is right sensor according to the scan it seems as if there is a issue with right sensor or do u guys think its becoz of left sensor acting up ?
10-27-2016, 03:15 PM
Adaptive cruise control problem
--and eventually got to ACC and got that same error immediately. When I got back and started looking car over, I pushed on bumper and it seemed strangely loose. Then I saw majority of screws missing in fender area on both sides. At that point it was clear someone did a hack job on it, likely at auction yard (...it was perhaps washed through). Obviously explained the ACC error I saw too. Very disappointed that car was labeled CPO. The checklist would not have been worth the toilet paper the tech skipped while filling it out in the John with a brewski or two in hand. Needless to say, i was on my way to the one I eventually bought in the next 5 minutes.
