TCS problems

[lutzdog]

I am having a wonderfull time with my TCS on the 97. If anyone is familiar and can help me work on this thing and resolve it I can give you a great deal on any kind of woodwork,cabinets,countertops that you may need. Hell i will cut ur grass for life if i can resolve this.

[Y2Kvert4me]

I am having a wonderfull time with my TCS on the 97. If anyone is familiar and can help me work on this thing and resolve it I can give you a great deal on any kind of woodwork,cabinets,countertops that you may need. Hell i will cut ur grass for life if i can resolve this.Can you describe the nature of the problem experienced, and/or any codes, and whether this is a new problem, or an ongoing issue you've had no success in solving.


:cheers:

[lutzdog]

The long saga started when i first got the vehicle. The active handeling engaged and reduced engine power so i disabled then re enabled and got home fine. I was getting on it so i didn't pay it any mind.

When i went to corvettes at carlisle on the way there it activated several times on the long trip and when i pulled in on sat going 4 mph it activated saying reduced engine power and the check engine light came on.

pulled into the parking spot a 1mph and turned the vehicle off and checked the dic got the following C codes
1255
1278

While there i asked the corvette guru and he basically told me that the culprit might be and sounds like the electronic ebtcm. Problem i later found out is that gm no longer makes this part so i scrounged one from a forum member off of a 97 that had 50,000 miles that had been wrecked.

Put that part on and seemed to be working fine it engaged a couple of times over the next month no codes though. then it engaged again and the service engine soon message displayed across the dic. I checked the codes and this time had the following C codes
1221
1281

Which was a sterring sensor and a lf wss sensor. I ran thru the diagnostics on the service manuals checked the grounds (all of them and cleaned them) checked the voltage on the wss go the required voltage. I then cleaned and checked the harness for the wss up front and back cleaning the connections and got the required voltage from them as well. Checked the ohms on the sensors they were within specs.

Having cleaned all the connections on the harness themselves is where i am at now and it did engage again. I am at a loss the only thing that i can think of now is replace the steering sensor and have a Front end alignment and balancing of the tires.

I can figure most things out but this could get expensive so i don't want to keep throwing pies at the wall replacing parts. Now if they are all bad i will get a third job to do it but u understand

[Y2Kvert4me]

Put that part on and seemed to be working fine it engaged a couple of times over the next month no codes though.When you say engaged....Do you mean the Traction Control is simply coming on as if you were spinning your tires (but when your not)?

If so, can you please post the exact tire sizes that are on the car.


:cheers:

[lutzdog]

It either says Tractions Sytem Engaged or Active Handeling Engaged when it happens. But funny you should mention the wheels spinning. I broke traction the other day on semi wet ground and went a little sideways with the rear and the handeling did not come on that time......... to be honest i have not tried to run the car hard yet. Not sure if that makes a difference.

I have 275/40ZR17's on the rims.

[Y2Kvert4me]

I have 275/40ZR17's on the rims.On all four? If so, that is likely the cause of the problem.


The other thing I'm not quite understanding, is that 97's didn't have Active Handling. The first cars to come equipped with it were the '98 Pace Cars, and then it it became an option for all other C5s in mid '98.


:cheers:

[lutzdog]

why do u say the tires are the likely cause? I do not understand that.

Also yes the 97 of course was the first year and yes the ******* year but they had active handeling or trac control. it is simple 1 mode not like the later years and the abs system is located directly behind the rear end and not in the front like the 98 and above.It does indeed have the wss in the hubs and all that good stuff

[lutzdog]

i can take pics if that would help

[Sneaks]

why do u say the tires are the likely cause? I do not understand that.
Also yes the 97 of course was the first year and yes the ******* year but they had active handeling or trac control. it is simple 1 mode not like the later years and the abs system is located directly behind the rear end and not in the front like the 98 and above.It does indeed have the wss in the hubs and all that good stuff

Because the TCS must see a difference in wheel speed. If the tires aren't at least a 1/2 inch bigger overall, in the rear, it thinks the wheels are spinning and engages the TCS.
Check your tire sizes again. 245/45/17 front, 275/40/18 in the rear are the stock sizes.
:thumbsup:

[lutzdog]

no the sizes are the same all the way around. when the vehicle was bought there were z06 rims the same size all the way around.

interesting. so all that would cause internal errors and steering sensor errors?all the stuff i have been experiencing?

[Sneaks]

no the sizes are the same all the way around. when the vehicle was bought there were z06 rims the same size all the way around.

interesting. so all that would cause internal errors and steering sensor errors?all the stuff i have been experiencing?

There's your problem. Change out those tire sizes in the rear, and all should be well again. :thumbsup:

[Y2Kvert4me]

no the sizes are the same all the way around. when the vehicle was bought there were z06 rims the same size all the way around.

interesting. so all that would cause internal errors and steering sensor errors?all the stuff i have been experiencing?The steering sensor could be a fluke, but is probably not related.


Here's how traction control works. There is a wheel speed sensor located in each bearing/hub on the car. These sensors are used for ABS as well, but for the sake of traction control, it compares the difference in wheel speeds front/rear.

In stock configuration, the rear tires are about 1" taller in height compared to the fronts. (Not just wheel dia, that is irrelevant, but overall diameter of the tire). Because the TC system is programmed for those tire heights, it "expects" to see the rear tires always turning slightly slower than the front. (larger diameter turns slower).

When TC does engage, it does two things, it applies braking to the rear wheels, and also severely retards engine spark timing, thus noticeably cutting off the power, until it senses traction is restored. This compounds the problem in a case like yours, as you never did lose traction, so restoring it is kinds of difficult.

So, giving an example of a more extreme situation than yours, say putting a taller tire on the front than what's on the rear, is a surefire way to run into unintended TC engagement. The TC logic "sees" the rears spinning noticeably faster than the fronts, and thus thinks the rear tires are spinning.

You, running same size all around, seems to be the borderline point where the problem randomly occurs. Some people claim to do the same and never have unwanted TC engagement, others have the same luck as you are having, and find it does occasionally falsely engage.

As Sneaks already alluded to, the "rule of thumb" is to keep the rear tires taller than the fronts. Even 1/4" taller usually works fine, but I always recommend at least 1/2" taller, just because tires are not cheap and I'd rather not suggest a size combination that could potentially be problematic to someone.

If you are running a 17x9.5 all around, going to a 255/40/17 size on the front (with the 275/40 on the rear) would probably solve your issue.
Finding a pair of 18" Z06 wheels for the rear would be another option, and open up more tire choices for you as well.


And, in the meantime, until you do figure out a permanent solution, simply shutting Traction Control off will at least prevent it's unexpected intrusion and power loss during your drive.


:cheers:

[Y2Kvert4me]

There's your problem. Change out those tire sizes in the rear, and all should be well again. :thumbsup:First thing I though of too, but there are VERY few taller size options manufactured that would fit a 17x9.5 wheel.

No one seems to make a 275/45 or 285/45/17". So I opted to suggest a shorter front tire instead.


:cheers:

[PortDawg]

It's amazing that the tolerances are so tight.

Phil - I know someone we need to go smack in the back of the head...You were looking at some new rims anyway right ?

[Sneaks]

First thing I though of too, but there are VERY few taller size options manufactured that would fit a 17x9.5 wheel.

No one seems to make a 275/45 or 285/45/17". So I opted to suggest a shorter front tire instead.


:cheers:

You make a good point. Shorter fronts would make things correct again. Didn't even think of that. :thumbs:

[lutzdog]

I guess going to a 255/40 17 would be cheaper than getting rims to put275/40/18 on the back. I have searched around for this answer as well and some say it works some says it does not so i guess the better option is to get the two front tires and see unless i can pick up some reall cheap rims.

This gives me another option.

[lutzdog]

also thought of this. does anyone have any stock rims that they would rent to me. I will provide an insurance rider it they so choose.

[Bill Curlee]

You should have posted in C5 TECH. You would have gotten a LOT more help quicker.;)

Anyway... In short,,,YES,,,the same size tires all the way around can and will cause TCS issues. Until you rectify that issue, its real tough to point you down other paths.

You also seem to have wheel speed sensor issues. Heres a FACT. From 97-2009,,,,,:toetap:,,,I have N E V E R seen a wheel speed sensor go bad. PERIOD. I have see wheel bearing assy's go bad (yes they are two separate assemblies. I have also seen sensor pig tail damage due to carelessness or an accident. The sensor part of the wheel bearing is just about bullet proof.

http://img.photobucket.com/albums/v402/bill327/FrontWheelhub.jpg

http://img.photobucket.com/albums/v402/bill327/FrontWheelhub2.jpg

http://img.photobucket.com/albums/v402/bill327/FrontHubSpeedsensor1.jpg

http://img.photobucket.com/albums/v402/bill327/FrontHubSpeedsensor2.jpg

http://img.photobucket.com/albums/v402/bill327/WheelHubspeedsensor.jpg

On another note, the wheel sensor wiring harnesses have female connectors that just plain SUCK. 90% of the problems that I see with WSS is due to female pin damage.

Heres an example of a good and BAD female pin The one on the LEFT is brand new:

http://img.photobucket.com/albums/v402/bill327/GOODBADconnector.jpg

The FRONT sensors use a jumper cable to connect the WSS to the main body connector:

http://img.photobucket.com/albums/v402/bill327/DSCF0037.jpg

The female pins in the female connectors go bad a LOT.

Anywhere theres a female pin,,,its susceptible and must be checked. I use a spare male pin to insert into the female pin and that tells me if the female pin has the correct grip on the male pin (sounds sexual doesn't:smilelol: )

Heres an example of the male pin:

http://img.photobucket.com/albums/v402/bill327/DSCF0012-1.jpg


I will say this. The Reduced Power problem has NOTHING to do with EBTCM or tire sizes. It involves the Throttle By Wire system. DTC 1281 (APP Sensor 2 Circuit ) caused that problem. Check the accelerator position sensor connector and wiring. If the problem persist, remove the sensor and read it with an ohm meter and make sure that the resistance reading is smooth and linear thru out the range of the peddle. The are Three sensors in one sensor One reads high going low and the other reads the opposite. The other does something else:;)

Something else to note: 97 and early 98 C5 had issues with the Throttle Actuation Control (TAC) module reliability. It was detailed in a service bulletin. The recommended fix if the car had specific problems causing it to go into reduced power (displaying specific DTCs) was to replace the TAC with a 99 or newer TAC module. I had a early 98 and had to replace the TAC module ($250)

You seem to have an issue with APP circuit 2 so, I would concentrate there first. Check that sensor.




BC

[GB Vette]

You should have posted in C5 TECH. You would have gotten a LOT more help quicker.;)



Good point Bill :takdir:

[WKMCD]

The traction control on the 97/98's is not as smart as the later years and not as sensitive to tire size. My 275x35x18 and 315x30x18 PS2's are pretty close and I don't have any traction control issues. That being said, running exactly the same tire height could be an issue.

BTW: Bill likes his grass cut to 3 inches - and don't forget to trim. :smilelol:

[lutzdog]

Thank you for your responce. I will change the tires in the front to reflect 255/40/17 size on the front (with the 275/40/17;s on the rear assuming this will be enough of a size difference?...correct want to be sure before i buy 2 tires).

Once that is done we will see if it engages the trac system anymore. That being said ,i have gone thru the entire harness and cleaned all grounds and checked the pigtails from the wss's and verified the same voltage reading. But to be on the safe side i will add those 4 pigtail harness's to my list of stuff to be replaced.

i will look up the locations of the other two modules and test them as well the one thing i am quite not understanding is the C1281 Steering Sensor Uncorrelated Malfunction code related to the throttle sensor and possibly the tac? I am just learning and reading everything that i can but i have trouble following the schematics just trying to see how those systems interact. Also to make sure when u r saying reduced power u r refferring to the trac system engaging.

[nedih rotaredom]

Well I have run 275/40/18 on all 4 in the 00'...............no issue.
Ran 275/35/18 on all 4 in the 97' at VIR.............2 days up to 170mph+ no issues.............EACH car can be different on this issue.
You can also clear the codes while driving via the dic. I drove the 97' to race day 450+ miles and back with a bad BCM.........97's are not reprogramable and I couldn't get one in time :banghead:

[PortDawg]

Thank you for your responce. I will change the tires in the front to reflect 255/40/17 size on the front (with the 275/40/17;s on the rear assuming this will be enough of a size difference?...correct want to be sure before i buy 2 tires).

Once that is done we will see if it engages the trac system anymore. That being said ,i have gone thru the entire harness and cleaned all grounds and checked the pigtails from the wss's and verified the same voltage reading. But to be on the safe side i will add those 4 pigtail harness's to my list of stuff to be replaced.

i will look up the locations of the other two modules and test them as well the one thing i am quite not understanding is the C1281 Steering Sensor Uncorrelated Malfunction code related to the throttle sensor and possibly the tac? I am just learning and reading everything that i can but i have trouble following the schematics just trying to see how those systems interact. Also to make sure when u r saying reduced power u r refferring to the trac system engaging.

Phil,

I'll help you with the schematics. I'm good at those. We'll get this thing fixed..


Jim

[Y2Kvert4me]

one thing i am quite not understanding is the C1281 Steering Sensor Uncorrelated Malfunction code related to the throttle sensor and possibly the tac? You and Bill are describing two different codes, this is why the confusion.

Pay attention to the prefix of the code if it happens again, as there is both a P1281 (PCM code - accelerator pedal position sensor), and a C1281 (TCS code - steering position sensor).

A P1281 could help trigger Reduced Engine Power mode, but will not by itself - it takes two or more APP codes to set REP mode.
A C1281 is not a PCM code, and can not in any way trigger REP mode..

All codes will have a H (history), and/or a C (current) suffix.


:cheers:

[pops98]

Lutzdog where are you located? I have my original wagon wheels that I want to keep, but if you are close, you can borrow them to see if that solves your problem. Heck the tread is not so good, but you should get a good test out of them.
Let me know.

After reading this thread, I am amazed by all the knowledgable people who visit this forum. I send a great big thanks to all posters for this information.

[lutzdog]

I live in Gloucester Va 23061. I would really appreciate it. U can call me at 804-695-6373.

[lutzdog]

I put the tires on this past weekend and did some pursuit driving reminesant of some other times and only had it activate when it slipped. I will over the course of the week drive it normally on a road trip and see what happens if that is the case my wife is not going to like the answer.

Thank you for letting me borrow them. I will try to keep some tread on them lol.

[pops98]

Great, sounds like you proved what the other smart people diagnosed. Did you get the TPS to train?
I would never have guessed the tire stagger. Have fun and if you have any tread left, it will be a bonus, Heck with the amount of tread on the tires, they kinda looked like slicks anyway.

[cscokd]

I've experienced many TCS related issues on my 98 C5 over the years. Bill Curlee is 100% correct on the female connector problems. 90% of the wss problems are these connectors.

But did you know that while driving and suddenly experiencing the Reduced Power symptom and TCS, ABS disabled, etc. Don't pull over and re-start your engine to clear these codes. If it was a spurious event, just turn you ignition key to the start position momentarily while driving. Your starter will not engage however the error condition will be cleared and diagnostic mode entered. If your condition was a one time event you will be good to go again. I've had to use this method many times on the track and it has saved my bacon most times.
cscokd