Hello, fellow Corvette Forum mates!

I got a coupon for a free oil change at the Chevy dealer and as I was leaving saw the DIC, "Service ABS, Traction Control, & Active Handling. Dealer wanted to screw me by charging me to replace my left front Hub for $900. I researched on here and checked the codes and got "28-TCS-C1225 H C" & "28-TCS-C1221H C". Based on my research this means I'm not getting a signal from my left front wheel sensor and I'm getting excessive speed variation.

I don't have any other reason (noise, roughness, etc. to think my wheel hub/bearings are bad. Maybe it's just a bad connection at the harness?

I wonder if anyone can tell me if it's possible for me to do it myself and get to the wire harness by using my ramps or do I have to get the car up high on a lift? Also, seems reasonable to just purchase a left wire harness for $30 bucks and see if that works. I have a 2003 Z06 with only 39,000 miles on it. The car still smells like new inside. I have to say this Forum has already saved me big time when I replaced a window regulator myself.

Cheers!




Update 4/27/10

I ordered a new Left Front ABS Sensor Harness (GMPartsDirect $45) and just replaced the old one with this new one. I would have done the swaping of left/right harness first but with my crummy jack it is very difficult for me to take the tires off and work under there. But it was fairly easy and straight forward to replace the harness. I did notice right away that the rubber stays were undone! Did they come out by themselves or did the crooked dealer do it? Who knows? Unfortunately, I continue to get "28-TCS C1221 H C" . I am no longer getting C1225. But I am still getting no input signal from the left front sensor. I wonder if there is something else I can try before biting the bullet on a new hub. I don't think I want to try and do that job myself. Thanks in advance!

 

You can get to the harness by removing the wheel. Check that the female pins at each end of the harness are not flattened.

 

Yes, I agree. Just remember that for things to work, clean and solid contacts must be there for the signals to get through.

 

Thanks, I'll try that first today.

 

Start with post #847:

http://forums.corvetteforum.com/c5-t...post1573338953

 

Update 4/27/10

I ordered a new Left Front ABS Sensor Harness (GMPartsDirect $45) and just replaced the old one with this new one. I would have done the swaping of left/right harness first but with my crummy jack it is very difficult for me to take the tires off and work under there. But it was fairly easy and straight forward to replace the harness. I did notice right away that the rubber stays were undone! Did they come out by themselves or did the crooked dealer do it? Who knows? Unfortunately, I continue to get "28-TCS C1221 H C" . I am no longer getting C1225. But I am still getting no input signal from the left front sensor. I wonder if there is something else I can try before biting the bullet on a new hub. I don't think I want to try and do that job myself. Thanks in advance!

Just another thought...I wonder if I went back under the car with the wheel off, and I was to hook up a multimeter set on low DC volts and spin the wheel around? Does that make any sense? Thanks!!!

 

You drove in to the STEALERSHIP and the car was FINE. You go to drive out and BOTH,,not one but B O T H front sensors dont work.

. "I did notice right away that the rubber stays were undone! Did they come out by themselves or did the crooked dealer do it?"

YOU BET YA!!!!!!

Closely examine the female pins in the harness connectror that the jumper cable plugs into. Make sure that the femele pins are not spread open. When they are spread they make poor contact. You can carefully bend them back with a metal pick. You can also fix the jumper harnesses. I bet ya there spread also.

Let us know how you make out

 

Yes, with one exception, the meter should be set to AC on the millivolt scale. Spin it as fast as you can, the output should be 100 mV AC or greater.

You can also check the resistance of the sensor itself, it should be 850-1350 ohms.

 

 

Did the tests today and I think they both passed. I hooked the alligator clips directly to the connector off the hub. I missed the class on reading multimeters, but with the meter set on 20M Ohms (Blue Omega symbol) I got a "1" which is the opposite of being open "0" (Or is the other way around?) Anyway, the ohms test showed that it was a closed circuit - not open. The other test was better. I set the meter on red 200 V and grapped on of the studs on the wheel and spun it around faster and faster. The meter gradually went from .1 to .5 to 1.0 and I almost got it up to 2.0. Basically, the faster I spun it, the higher it got. This makes sense if the ABS Sensor in the hub is working, doesn't it? So if my sensor/hub is good; and I put on a new harness...could the trouble still be in the two connectors or maybe something else down stream? Thanks in advance!!!

 

This is most likely your issue. The connector on the right is BAD.. The one on the left is new.



Exmine EACH female connector and look for spread pins. If there spread, it will not work properly. I use an old male pin to test my female pins... There should be a nice firm grip on the male pin when it is inserted an retracted. If not, it bad

 

Hello Bill,

I checked the female side of the jumper harness (which plugs into the hub wire) and it looks good (probably because it is a brand new harness).

I also checked the female end of the main chasis harness and it may have the problem you describe. Does this mean replacing the whole chasis wiring? Or can it be bent back? Is there a spray or something good for spraying onto contacts to make them work better?

I did another test as follows: this time I plugged in my new harness at the hub and check resistance and voltage at the end of the harness and the result was the same as before; good closed circuit and voltage increasing with wheel speed.

What's next? Do you happen to know the exact location of the ground plug associated with the left front sensor? Maybe I could clean that up some.

Thanks,

John

 

John

There is NO spray that will help you with this issue. You MUST get the female pin rebent. Use a small metal pick and carefully bend the little tab back down. Once its bent back in place, carefully reinstall the male connector back on to the female connector.

You can purchase some ANTI CORROSION spray specifically designed to stop FERT COROSION. DO NOT USE Silicone Compound inside the electrical connections. Apply it on the RUBBER seals only

BC

 

IF,,,,,the female connector happens to be unrepairable, you can purchase a new replaceable pig tail replacement plug. Gene Culley has the bast price.

 

I took a small jewelers screwdriver and got it bent back...put back together and test drove...no luck. Still get a TCS C1221 HC. It seemed to be a tight fit though when I pugged it in. I know I'm getting signal at least to the end of the jumper harness, darn it!!!

 

Try autozone for the replacement hub if you need it. It's a fraction of the price from a dealer.

 

Pop off the MAIN EBTCM connector and measure EACH wheel sensor from there. When I get home I can forware you the pin # to sensor info.

Bill

 

Why should I replace it if it's still good? I tested it with a multimeter and it passed both the resistance and voltage tests. Dang it! I wish I knew where the left front harness ends up so I can test it there too. If someone could tell me the location of either the ground plug associated with the left front sensor or the place where it goes into the EBCM "brain" module. I would like to see if the signal is getting that far.

Thanks,

John

 

Where is it located? The Main EBTCM Connector? I will be connecting the multimeter test leads to the pins coming from the left front? Sounds good. My email is jcorina@hotmail.com. Plus, it's almost 5 O'Clock! Thanks, Bill

 

This is the harness end that you will read with the meter. The red part of the connector contains the pins you want:





BC