06 A8L possible ABS module issue
05-27-2018, 08:05 PM
#1
06 A8L possible ABS module issue
hi, first post after becoming Audi owner.
Just bought this A8L with knowing abs, brake highlight warning lights on dash. Red a lot of posts from here regarding the ABS issue.
Ordered a VCP, which is still on the way. Tried a freeware checking the code and pulled two used abs modules for testing.
I only have two abs modules pulled from 4B0 614 517 and 8E0 614 517 instead 4E0 614 517 BC. I know they are not 100% match but that is all I can get.
here is the problem, ABS is still unknow from the freeware after swap with the used one.
Is it so true that even the can bus would not work with silightly mismatch but same Bosch 5.7 module? Or indeed there is a wiring issue from the harness?
Many thanks
Just bought this A8L with knowing abs, brake highlight warning lights on dash. Red a lot of posts from here regarding the ABS issue.
Ordered a VCP, which is still on the way. Tried a freeware checking the code and pulled two used abs modules for testing.
I only have two abs modules pulled from 4B0 614 517 and 8E0 614 517 instead 4E0 614 517 BC. I know they are not 100% match but that is all I can get.
here is the problem, ABS is still unknow from the freeware after swap with the used one.
Is it so true that even the can bus would not work with silightly mismatch but same Bosch 5.7 module? Or indeed there is a wiring issue from the harness?
Many thanks
05-28-2018, 02:30 PM
#2
AudiWorld Super User
Need a real scan from VCDS.
Right now your issue seems unknown, including if it is even in the ABS module to start with. I have not heard of people ever trying a module from other models, and various settings presumably won't liine up or be calibrated correctly. 4B0 is maybe a C5?--having owned one a lot more prone to ABS module failure than D3's. 8E0 would be like a Q5/B8 A4/5.
With a decent scan you can see if it is a wheel sensor, wiring or ABS control module, and see if it has a code saying ABS module defective. Freeware and their "cheap" EBay/Amazon cables are usually useless beyond ECU; same basic problem as a generic OBDII code reader. The majority of ABS issues D3 owners have are 1. wheel sensors
2. wiring going out to sensors, especially in rear, 3. wiring in first few feet below the ABS unit under hood where the whole harness starts falling apart insulation wise, and then 4. the ABS module issue.
Right now your issue seems unknown, including if it is even in the ABS module to start with. I have not heard of people ever trying a module from other models, and various settings presumably won't liine up or be calibrated correctly. 4B0 is maybe a C5?--having owned one a lot more prone to ABS module failure than D3's. 8E0 would be like a Q5/B8 A4/5.
With a decent scan you can see if it is a wheel sensor, wiring or ABS control module, and see if it has a code saying ABS module defective. Freeware and their "cheap" EBay/Amazon cables are usually useless beyond ECU; same basic problem as a generic OBDII code reader. The majority of ABS issues D3 owners have are 1. wheel sensors
2. wiring going out to sensors, especially in rear, 3. wiring in first few feet below the ABS unit under hood where the whole harness starts falling apart insulation wise, and then 4. the ABS module issue.
Last edited by MP4.2+6.0; 05-28-2018 at 03:41 PM.
05-28-2018, 03:17 PM
#3
AudiWorld Senior Member
Other than the ABS and brake light, what if any other symptoms are you getting? How many miles on car? Are the ABS and brake light continuous or do they happen after a few miles of driving? Also, is your speedometer working all the time?
One other thing you might try is disconnecting the connector to the ABS module. Blow off any dirt and crud before working the release lever to make is easier to move he lever and move it slow. When you get the connector off, spray the contacts (both male and female with contact cleaner, the blow dry with air.
As for swapping the ABS module, I echo the others. When (and if) you determine the ABS module is bad, then you can have the fun of removing it. (really tight space to get the screws off). It can be removed without disconnecting the brake lines on the brake modulator. I did it on an 05 A8.
One other thing you might try is disconnecting the connector to the ABS module. Blow off any dirt and crud before working the release lever to make is easier to move he lever and move it slow. When you get the connector off, spray the contacts (both male and female with contact cleaner, the blow dry with air.
As for swapping the ABS module, I echo the others. When (and if) you determine the ABS module is bad, then you can have the fun of removing it. (really tight space to get the screws off). It can be removed without disconnecting the brake lines on the brake modulator. I did it on an 05 A8.
05-28-2018, 04:26 PM
#4
Thanks.
Abs, brake, adaptive light are constantly on. Park brake is error after trying to engage. Speedometer is always zero. mileage is 200+ k Kms.
I tried disconnecting the harness from abs module, no difference.
4B0 came from Passat. 8E0 came from A4. , can not find any A8. My theory is they are mismatch and will throw code and lights. But it should communicate.
yes, I am waiting for vac and expect no code as no communication can be established.
yes, the space is very tight. I am not confident I can remove it.
Abs, brake, adaptive light are constantly on. Park brake is error after trying to engage. Speedometer is always zero. mileage is 200+ k Kms.
I tried disconnecting the harness from abs module, no difference.
4B0 came from Passat. 8E0 came from A4. , can not find any A8. My theory is they are mismatch and will throw code and lights. But it should communicate.
yes, I am waiting for vac and expect no code as no communication can be established.
yes, the space is very tight. I am not confident I can remove it.
05-28-2018, 04:50 PM
#5
Thanks.
Abs, brake, adaptive light are constantly on. Park brake is error after trying to engage. Speedometer is always zero. mileage is 200+ k Kms.
I tried disconnecting the harness from abs module, no difference.
4B0 came from Passat. 8E0 came from A4. , can not find any A8. My theory is they are mismatch and will throw code and lights. But it should communicate.
yes, I am waiting for vac and expect no code as no communication can be established.
yes, the space is very tight. I am not confident I can remove it.
Abs, brake, adaptive light are constantly on. Park brake is error after trying to engage. Speedometer is always zero. mileage is 200+ k Kms.
I tried disconnecting the harness from abs module, no difference.
4B0 came from Passat. 8E0 came from A4. , can not find any A8. My theory is they are mismatch and will throw code and lights. But it should communicate.
yes, I am waiting for vac and expect no code as no communication can be established.
yes, the space is very tight. I am not confident I can remove it.
check out CHEAP Bosch 5.3 ABS REPAIR VW Passat Audi A4 A6 A8 S4 from the left tabs, select "ABS Removal" and you will find videos that will show you how to remove it without disconnecting lines..
05-28-2018, 07:44 PM
#6
AudiWorld Senior Member
Some will disparage me for making a diagnosis with a VAG. I feel confident in saying the problem is definitely the ABS module. For $150 or so, Cheap ABS will repair it. It is however a pain to remove it. Send me a private message and I will give you detailed information on how I did it on my 05 A8. FYI, my hands are huge, If i can find them my glove size is XXXL. I'm also 73 yrs old.
check out CHEAP Bosch 5.3 ABS REPAIR VW Passat Audi A4 A6 A8 S4 from the left tabs, select "ABS Removal" and you will find videos that will show you how to remove it without disconnecting lines..
05-29-2018, 01:45 AM
#7
Thanks. A8 is opposite with others and make it harder, in my opinion, to remove one screw. I have not seen any video that work on A8 yet.
I will tr to measure conductivity on can bus but not sure the schematic yet.
I will tr to measure conductivity on can bus but not sure the schematic yet.
Trending Topics
05-29-2018, 05:17 AM
#8
AudiWorld Senior Member
It can be done on a D3 A8. I started to create a video and told Matt (owner of CheapABS) that I'd send him a video. Unfortunately, i did not know how to splice several parts of the video together and edit it so it never happened.
06-03-2018, 01:01 PM
#9
The vcp is still on its way. So I took a measurement of power supply.
Constant 12v is available at pin 2 and 6 of abs coupler.
If if anyone could tell me which 2 pins are for can bus. I can hook up an oscilloscope and monitoring anything from outside of ABS.
Both front speed sensors have new fastener, indicates they might be replaced recently.
Besides tri-lights, non speedometer and ding-dong alarm. The power steering is unavailable and steering wheel is at 2 o'clock.
thank you.
Constant 12v is available at pin 2 and 6 of abs coupler.
If if anyone could tell me which 2 pins are for can bus. I can hook up an oscilloscope and monitoring anything from outside of ABS.
Both front speed sensors have new fastener, indicates they might be replaced recently.
Besides tri-lights, non speedometer and ding-dong alarm. The power steering is unavailable and steering wheel is at 2 o'clock.
thank you.
06-05-2018, 12:36 PM
#10
Measurement shows some strange reading with engine running or only accessories.( press button on first stop)
Both 24 and 40 of CAN bus has some activities but p-p is only 1.2 v.
23 of Ignition On only has 0.24 V.
Assuming Can is okay but Ignition is wrong for sure.
Both 24 and 40 of CAN bus has some activities but p-p is only 1.2 v.
23 of Ignition On only has 0.24 V.
Assuming Can is okay but Ignition is wrong for sure.
