I'm getting these messages in the DIC and they keep coming back within a few minutes of pushing "Reset":

Service Active Handling
Service ABS
Service Traction Control

The only codes I currently have are C1233H and C1283H

I have had some battery and battery charging issues in the past (Battery Tender malfunctioned and boiled one of the batteries down low on water, one cell nearly all the way), but new battery installed now and new BT.

About the time I was having battery trouble I also got a check charging system message in the DIC but no other messages and the check charging system message only appeared once. I did not look for codes at that time as everything seemed to be operating properly.

Shortly after that the DIC began displaying Service Active Handling, Service ABS, and Service Traction Control. A check of codes then showed I had all of these:

C1282HC Yaw Rate Sensor Bias Circuit Malfunction

C1284HC Lateral Accelerometer Sensor- Self Test Fault

C1285HC Lateral Accelerometer Sensor Circuit Malfunction

C1287HC Steering Sensor Rate Malfunction

C1288HC Steering Wheel Position Sensor

C1296HC Master Cylinder Brake Pressure Sensor Circuit Open Or Shorted

Additionally there were two other TCS codes stored:

C1233H RF Wheel Speed Circuit Open or Shorted

C1237H High System Supply Voltage

I no longer have any of the codes above except for C1233H and the new one, C1283H. Because these are history codes does this mean the fault is no longer present and if so why can't I extinguish the three DIC warnings for ABS, Active Handling and Traction Control?

The Helms Manual says an EBCM relay may have switched off these circuits when it sensed over voltage and will have to be reset with a Tech-2 or I can wait 100 ignition cycles and the EBCM will do that if it does not detect a recurrence. Am I on the right track before I start checking and cleaning all the grounds? 04 with 2K miles.

 

I suspected the codes were somehow connected to the previous battery issue but I have not been able to reset the DIC to erase the Service ABS, Active Handling and Traction Control warnings after I replaced the battery. I guess it could be a coincidence the C1233H is a legitmate code that happened to occur around the same time but I don't understand the C1283H. The car has never been apart or serviced in any way in that area and it only has a little over 2K miles. Is it possible the C1283 is a result of C1233, a wheel speed sensor not reporting so the EBCM is not getting enough information to decide if the steering is on center?

Now the $64,000 question I need the answer to right now (drum roll please...): Are there situations where old codes are present which cannot be reset without a Tech-II scanner? In other words, it cannot be done from the the car's on board diagnostics?

Thanks, Greg

 

Yep, the procedure in the video is what I am doing. I realize if faults are present they will have to be corrected before I can successfully erase fault codes. The reason I am posting for help is the codes I have (C1233H and C1283H) look like history codes rather than current failure codes and if this is true I should be able to erase them, correct? If the codes had said C1233HC and C1283HC I would not have asked the original question that way. I would realize I have problems which will need to be located first. If I understand correctly what you are telling me is the fault code suffix is not necessarily reliable. I may in fact have a current problem which is being reported by the EBCM as past history and not current.

(Trying to understand... Is it the C5 or is it me?)

Thanks, Greg

 

Many thanks for taking the time to explain it. You have cleared up what was a mystery to me. I don't know that I have ever read that concise a description here on how it all works.

Regards, Greg

 

I think we finally have it... one code remaining and it's current, C1233HC

RF wheel speed sensor. Unplugged and re-plugged the associated WeatherPak connector for a quick attempt but no go so guess I'll remove the wheel and check it with an ohmeter and for voltage when I spin the wheel. Wonder what the usual failure mechanism is on these?

Thanks, Greg

 

RF wheel speed sensor measures 1100 ohms and has voltage output on the AC millivolt scale when I spin the wheel. I can reset the C1233HC code which turns the warning lights out on the dash, drive the car and get the lights and code again within a few feet.

 

Theres a very good chance the FEMALE pins in the connector on the chassie are spread apart or damaged. Closely check the female pins and make sure that there not spread apart.

You can bend the tab back and male it make a better connection.


The output of the sensor is AC. If your getting an output, the sensor is good.

Bill

Bill

 

Thanks Bill,

I removed the 30 inch long two conductor jumper harness for testing and it measured .2 ohms on both legs so I assume the jumper harness is OK. I also have output on a DMM AC millivolt scale at the jumper harness male terminals when spinning the wheel so I assume the RF wheel speed sensor is OK. I do have some spare male and female terminals so next on the list is checking the quality of the connections at the chassis harness connector. Is this the final check point for diagnosing C1233 or are there other connections beyond this one I might need to check. Really appreciate all the advice and guidance Bill and 8VETTE7!

Regards, Greg

 

You can unplug the main connector on the EBTCM and read everything there.

BC

 

Update:

I reset all the codes and most disappeared except for C1233HC and a new one, C1283HC (steering wheel off center) which was weird because this car has not ever been taken apart in any area and certainly the steering shaft has not been touched. Both C1233 and C1283 remained and persisted and because there was no EBCM failure code that I could see (such as the infamous C1214 or C1255) I launched into posting a lot of questions here and checking grounds and connections over the past years, etc. Since I don't need the car for transportation it was not particularily important that it get fixed right away so I just researched it in my spare time and tried things from time to time. At first I was convinced my problem was somewhere in the vicinity of the RF wheel speed sensor so I checked resistances in the wiring and connections and checked for voltage output on the AC millivolt scale and I had that. Finally after four years I called Jason Durr the Corvette specialist at City Chevrolet and he told me I was probably wasting my time trying to figure out the codes and just bring it in and get a new EBCM so I did.

Jason installed a new $1000 EBCM and informed me a few minutes later my car was fixed and he was right, now it is.

 

Because of all the EBCM failure reports I did ask if a secret warranty existed but sadly that's not the case or so I was told.

I was hoping they would let me have the old one so I could take it apart to see if I could find anything obvious or maybe send it off to find out what failed but they said they needed to return it for a core and I didn't want to pay to keep it. So... that's the story. Sometimes you just have to shell out some dough I guess.

I hope C6 electrical is improved because I have been thinking about a Z06.