got the car back from the gm dealer, results=not good and depressing, bad EBCM
12-28-2011, 07:51 PM
#1
got the car back from the gm dealer, results=not good and depressing, bad EBCM i have a 1998 z28 m6 car.....the ten bolt broke a while back, and replaced with an s60......now im have traction control issues, and the dealership beleives that the electronic brake control module (EBCM) is to blame......now im here seeking your guys help in deciding if thats the issue....heres the story
10 bolt broke and car sat for 2 monthes not being driven, but started every other week.....it was then driven to 500 feet to my neighbors, where it stayed on jack stands for a month or so with the stock 10 bolt removed,and the wheel speed sensor connectors just hanging (its a 4 channel)....i then installed an s60 with 373s in it, and kept the 4 channel.......when i installed the s60, i installed it without the parking brakes, because i accidently sold them with the rear and needed to get new ones........strange shipped the rear with the parking brake hardware inside the backing plate, with the 2 nut thingys zip tied in......i forgot to remove those pieces, and began driving the car.........after a mile or so, i hear a deep grinding noise, and return home.......pulled the wheel and discovered that the parking brake hardware came out of the backing plate, and was grinding on everything........it semi rounded over some of the stud heads, and also gave the reluctor ring some very very very tiny scratches........i put wheel back on, then removed the hardware from the other side to prevent that from happening......i then drove thinking it was fixed, only to find that after 15 mph, low trac light would come on.......pulled wheel again, and the sensor was bent......installed new sensor, and now everything was fine......during this period, i also rewired the power driver seat, and accidentloy forgot to disconnect the battery, and while rewiring it, the pos and neg wires touched and created a big spark and some smoke (ill explain this significance in a bit).....i then drove the car and everything was fine, until i reached 115 mph, where everytime, i get the low trac light, and will not go away until i go 110 or less.....with the low trac light on, when i tap the brakes, they are pulsing and i barely have any brakes because anti lock is kicking in.....every now and then after i returned to normal speeds, i would randomly out of nowhere get abs inop, BRAKE, and asr off lights, and wont go away until i stop and shut the car off, then when i turn it back on, they are all still on until i go about 1000 feet or so then they are off........took it to the dealership and they found stored codes
c0046 and c0056, left and right rear wheel speed sensor fault
c0056 right rearwheel speed sensor circuit malfunction
u1255 SDL communication
they did check the tolerance between the wheel speed sensor, and the reluctor wheel, and both are slightly out of range, but when they drove it under 80 mph, all 4 wheels speed matched, meaning that they were still functioning.....they plugged their fancy gm toools into it, but when they went over 80 mph, the sensors didnt work.........what would happen was say they went 90 mph, all 4 wheels read 80 mph, and if they did 95, the wheels still read 80....but when they lowered the speed to under 80, all wheels matched the speedometer again.........why is that?so they say that their best bet is that the EBCM is bad, and thats 1045 plus labor to replace if i got a new one........they think that i may have fried it when the two wires from the power seat accidently touched.........does that sound like my problem LS1tech? sorry for the long post but i really wanna figure this out
10 bolt broke and car sat for 2 monthes not being driven, but started every other week.....it was then driven to 500 feet to my neighbors, where it stayed on jack stands for a month or so with the stock 10 bolt removed,and the wheel speed sensor connectors just hanging (its a 4 channel)....i then installed an s60 with 373s in it, and kept the 4 channel.......when i installed the s60, i installed it without the parking brakes, because i accidently sold them with the rear and needed to get new ones........strange shipped the rear with the parking brake hardware inside the backing plate, with the 2 nut thingys zip tied in......i forgot to remove those pieces, and began driving the car.........after a mile or so, i hear a deep grinding noise, and return home.......pulled the wheel and discovered that the parking brake hardware came out of the backing plate, and was grinding on everything........it semi rounded over some of the stud heads, and also gave the reluctor ring some very very very tiny scratches........i put wheel back on, then removed the hardware from the other side to prevent that from happening......i then drove thinking it was fixed, only to find that after 15 mph, low trac light would come on.......pulled wheel again, and the sensor was bent......installed new sensor, and now everything was fine......during this period, i also rewired the power driver seat, and accidentloy forgot to disconnect the battery, and while rewiring it, the pos and neg wires touched and created a big spark and some smoke (ill explain this significance in a bit).....i then drove the car and everything was fine, until i reached 115 mph, where everytime, i get the low trac light, and will not go away until i go 110 or less.....with the low trac light on, when i tap the brakes, they are pulsing and i barely have any brakes because anti lock is kicking in.....every now and then after i returned to normal speeds, i would randomly out of nowhere get abs inop, BRAKE, and asr off lights, and wont go away until i stop and shut the car off, then when i turn it back on, they are all still on until i go about 1000 feet or so then they are off........took it to the dealership and they found stored codes
c0046 and c0056, left and right rear wheel speed sensor fault
c0056 right rearwheel speed sensor circuit malfunction
u1255 SDL communication
they did check the tolerance between the wheel speed sensor, and the reluctor wheel, and both are slightly out of range, but when they drove it under 80 mph, all 4 wheels speed matched, meaning that they were still functioning.....they plugged their fancy gm toools into it, but when they went over 80 mph, the sensors didnt work.........what would happen was say they went 90 mph, all 4 wheels read 80 mph, and if they did 95, the wheels still read 80....but when they lowered the speed to under 80, all wheels matched the speedometer again.........why is that?so they say that their best bet is that the EBCM is bad, and thats 1045 plus labor to replace if i got a new one........they think that i may have fried it when the two wires from the power seat accidently touched.........does that sound like my problem LS1tech? sorry for the long post but i really wanna figure this out
Last edited by Floorman279; 12-28-2011 at 08:03 PM. Reason: .......
12-28-2011, 08:21 PM
#3
there is no way to fix the gap that i know off, if anybody knows how please let me know......but if that was the case, the front wheel speed sensors shoulda stll been reading 90 mph when they were doing......they read 80 and wouldnt go any higher just like the rears
12-29-2011, 09:22 AM
#5
Is the gearing on your S60 the same as stock? If so, nothing you do will make this stuff work. You may want to consult a tuner. (The dealer is going to be lost.)
What size tires are you running on the front/rear? If those are not stock, it could be compounding the problem.
My bet is that if you put a rear end back in with the stock gearing, all of this will go away. The ABS/TCS module will look at the car's speed, wheel speed, and other parameters to tell when your wheels are slipping. If the wheel speeds (front to back) are off or your wheel speeds don't match what the car expects for a given car speed, the control modules will be very confused.
What size tires are you running on the front/rear? If those are not stock, it could be compounding the problem.
My bet is that if you put a rear end back in with the stock gearing, all of this will go away. The ABS/TCS module will look at the car's speed, wheel speed, and other parameters to tell when your wheels are slipping. If the wheel speeds (front to back) are off or your wheel speeds don't match what the car expects for a given car speed, the control modules will be very confused.
12-29-2011, 11:19 AM
#6
car has stock 245 50 16s all around, its a four channel so the size of the gear shouldnt be a factor since it reads off each individual wheel........what i dont get is that under 80 mph all 4 wheels match the speedometer......it was already taken to a tuner after the problem started.....he did a street tune on it, and also recalibrated the speedometer for the gear change.......the problem was there when it was taken to the tuner, and its still exactly the same after the tuner.......tons of guys do a gear swap with a 4channel rear, and im sure that only a few have had any kind of issues, so i would think that the size of the gears would make it mess up
12-29-2011, 11:52 AM
#7
On The Tree
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It could be when you disconnected the brake lines on the rear. I have read where the traction control cars must be bled using a scan 2 devise or something like that. I can't remember the exact name. Read up on that. I have heard you can get a light from improperly bled brakes on Traction Contoll cars. You would think the dealer would have caught it. However I have seen it all. Just do a little research on Traction control brake bleeding. Could be your problem.
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12-29-2011, 03:29 PM
#9
Here's a good article on the ABS sensors: http://www.wellsve.com/sft503/counterp_v11_i4_2007.pdf Towards the bottom of page 1, they start talking about false activation and point out that an improper gap between the sensor and ring can lead to a bad signal. It also has some other ideas like a scratched ring or loose bearings.
12-29-2011, 11:13 PM
#11
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The EBCM # for a 98 TCS car is a 12453253.
Not totally convinced the EBCM is totally at fault.
It's possible yes.
Not super common though for this type failure.
Your problem start after the rear axle swap & then the problems afterwords.
That & most codes point to the rear axle WS sensors.
Find that too much of a coincidence IMO.
The wheel sensors on these cars are of the permanent magnet generator type.
They also produce an A/C voltage, greater as speed increases.
The EBCM has to use this voltage & amplitude signal to determain wheel speed.
The wiring is important as well as the gap. They both affect the sensor's performance.
There is no tuning possible here so thats not an option.
Not totally convinced the EBCM is totally at fault.
It's possible yes.
Not super common though for this type failure.
Your problem start after the rear axle swap & then the problems afterwords.
That & most codes point to the rear axle WS sensors.
Find that too much of a coincidence IMO.
The wheel sensors on these cars are of the permanent magnet generator type.
They also produce an A/C voltage, greater as speed increases.
The EBCM has to use this voltage & amplitude signal to determain wheel speed.
The wiring is important as well as the gap. They both affect the sensor's performance.
There is no tuning possible here so thats not an option.
12-30-2011, 01:13 AM
#12
The EBCM # for a 98 TCS car is a 12453253.
Not totally convinced the EBCM is totally at fault.
It's possible yes.
Not super common though for this type failure.
Your problem start after the rear axle swap & then the problems afterwords.
That & most codes point to the rear axle WS sensors.
Find that too much of a coincidence IMO.
The wheel sensors on these cars are of the permanent magnet generator type.
They also produce an A/C voltage, greater as speed increases.
The EBCM has to use this voltage & amplitude signal to determain wheel speed.
The wiring is important as well as the gap. They both affect the sensor's performance.
There is no tuning possible here so thats not an option.
Not totally convinced the EBCM is totally at fault.
It's possible yes.
Not super common though for this type failure.
Your problem start after the rear axle swap & then the problems afterwords.
That & most codes point to the rear axle WS sensors.
Find that too much of a coincidence IMO.
The wheel sensors on these cars are of the permanent magnet generator type.
They also produce an A/C voltage, greater as speed increases.
The EBCM has to use this voltage & amplitude signal to determain wheel speed.
The wiring is important as well as the gap. They both affect the sensor's performance.
There is no tuning possible here so thats not an option.
12-30-2011, 10:31 AM
#14
when the techs drove it, the front and wheel speed sensors read accurately until 80......when they went above 80 mph, all sensors said 80......they took it up to 95, and at 95, all wheels said 80, but the second they dropped below 80, the sensors were accurate again
12-30-2011, 05:04 PM
#15
Would probably need a ABS expert to decipher this behavior. I've had readings like this on other modules due to the slow speed of the OBDII interface. Maybe its normal, an indication of something centrally going wrong, or the module going in to a steady state condition?
07-09-2012, 09:03 AM
#16
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Digging up an old post. I am having the same issue as well. I have an s60 with 4.10 gears and have the same issue. Fine at any speed below 75-80mph. After crusing at that speed the light comes on after about 15minutes. Resets after I cycle the ignition.
OP did you get a fix for this?
OP did you get a fix for this?
07-10-2012, 10:24 AM
#17
well, my buddy has the car now.....before i old it i wapped a ten bolt back in and no issues since.......not getting into how, but my reluctor wheel on the rear had some very minor scratches and scores on the one side.........after the ten bolt was is, there were no more issues......it seems like the scratches were making it read off....like sometimes it could read and other times no, since you could drive for a while and be fine and other times you couldnt........check the condition of the relucotrswheels is all about i could tell you..........are your tire sizes on the front and back the same?
07-10-2012, 11:08 AM
#18
Launching!
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All the same tire/wheels stock 16 snowflakes.
I was reading more on it and it seems anything other than stock gear ratio can have issues. I guess its not too bad. Its gone next time the car starts anyway.... I am just picky about stuff like that.
I was reading more on it and it seems anything other than stock gear ratio can have issues. I guess its not too bad. Its gone next time the car starts anyway.... I am just picky about stuff like that.
