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Hey all.
Hoping for some guidance on next items to check.
Car is a 2000 frc with 70,000 mi. ABS/TC dash lights came on while on road trip to Corvettes at Carlisle this past August. No prior issues with this in the 3.5 years I have owned.
abs tc lights on and service vehicle soon message
Codes are as follows:
TCS no comm
PCM P1571
SDM U1040
Same codes appear after clearing. New fully charged Optima Red Top battery. No blown fuses (checked with meter)
have not checked the frame rail ground packs yet - is that the next logical item to check?
Hoping some of the experts on here can list in order what I should be checking.
Car runs and drives fine, but those damn abs and tc lights just bug the hell out of me!
Any help would be much appreciated.
Ok The traction control and ABS braking system both use the 'wheel speed sensor" data-------------------The traction control uses the data tp prevent the wheels from spinning on a hard launch ----The ABS system uses the data to prevent the wheels from skidding on a hard stop
Typically if you get both ABS and TC codes or warnings is because you have a bad wheel speed sensor----one is located at each wheel The pigtails often get fouled in wet whether and simply need to be cleaned--or you have a frayed or broken wire on the pigtails Last would be you have a bad wheel speed sensor
Anyone with a good scanner can isolate exactly where the issue lies
PS another common issue that can create the same symtoms is :
If you have changed tire heights different from stock
You can alter tire heights however the wheel speed sensor data cannot be changed otherwise both the ABS and TC won't work as desigend You MUST always retain the stock heights from front to rears ( that being the rears are 1" taller) This is not tunable for both ABS or TC-----When changing tires always try to keep the difference in heights from front to rear as close as you can to 1"-----------------
Appreciate the reply. So at this point you would focus on the wheel speed sensors and not the ebcm? I was thinking the no comm message was going to point to issues with the ebcm.
Tire size and height have not been changed.
Is there a sticky or thread that explains the proper steps and order of steps to diagnose when these codes are present? Seems like many people have had the same codes as I have.
I know i’m jumping ahead a little, but another question.... car is a 2000 - I know many 01-04 owners have done the re solder repair on the ebcm. Assume there is still no fix for the 97-00 ebcm?
A bad wheel speed sensor will not cause a TCS no comm code. If a wheel speed sensor is bad the code will be reported on the dic indicating which wheel is involved.
I thought I had read an extensive thread on how to properly diagnose this scenario - I remember Bill Curlee and others helping someone thru the process to determine if the ebcm was bad. I just can’t find it. Just trying to find an order of what to check before assuming the ebcm is bad. Also is there still no repair for the 97-00 ebcm (if it turns out being the culprit)?
No comm from the TAC can be because of a poor power supply or bad connection. This can be checked with a meter or high grade scanner. If there is no power supply problem that only leaves a bad ebcm. The PCM 1571 is not a good sign. As far as I know there is still no repairs that can be done on the older ebcm.
1571 is caused by a lack of control torque signal . The PCM supply + 5 volt to the EBCM . The EBCM toggles this to ground as mentioned below .
You should inspect the PCM and EBCM connector for bad/bad continuity .
If the +5v from PCM is present on term. 25 on the EBCM the EBCM is probably not function properly.
If you had a scann tool like Tech 2 and able to get contact with the EBCM this could probably be verified better
Thanks for taking the time to respond. Sounds like that is where I will start. Hoping it’s not a bad ebcm. Being a little aged, I am not too concerned about driving and enjoying the car without abs and tc. Didn’t have it growing up, and I survived right?
It’s just those damn warning lights though.....
Is it common for them to just give out without any warning or intermittent issues?
TCS no communication help
