Car – 2003 C5Z

Issues started after I pulled the differential for a rebuild.

I dropped the subframe, so the wheel speed sensors, VSS, 8-pin connector on the passenger side chassis, and the harness ground on the driver’s side had to be removed.

Everything plugged back in and installed and took it for a test drive.

The first test drive at low speed went fine, no codes no issues.

Then, the second test drive a little later and a little higher speed, I got “service traction control, service, ABS, service active handling, ding ding ding low power mode”

Good thing I was close to home and was able to plug in the Tech2, and pull codes from the DIC which are the following:

U1255

U1301

U1096

U1000

U1016

U1064

C1248

I can clear the codes using the onboard DIC and they will go away for a low speed drive. If I go over ~45 miles an hour roughly or accelerate semi rapidly it will throw errors on the dash for “service traction control, service, ABS, service active handling, ding ding ding low power mode”

What I have done to try to figure on the issue:

Check the plugs for the VSS, Wheel speed sensors, ground, and the 8 pin connector on the ABS harness in the rear. I am assuming the issue is in the rear since I had all of that disconnected. This did not fix the issue.

Checked the AC voltage was about 100mV for the wheel speed sensors, both passed.

Checked the resistance on both rear wheel speed sensors, both passed.

De-lumed all the wiring on the ABS harness in the rear to check for damaged or broken wires. Everything looked “ok”.

Checked the plugs for all the connectors in the rear visually and the look and feel fine.

At this point I am stumped and do not want to start replacing parts.

I know “U” codes are for the datalink not communicating. It just seems weird that all of this popped up right after I had the rear cradle out. . . Thank you for any help.

 

Does the EBTCM error out at exactly the same speed every time? I know that you stated "under moderate to heave acceleration but, I need to know if it is a specific speed related event.


My 02 ZO6 had an issue that would trip the EBTCM out at exactly 48 MPH. A buddy had the same issue and his would trip at 103 MPH.

Let us know.

Bill

 

i have all the wiring unhooked again. anything else i should check before buttoning it back up again?

I will check the speed trip point ASAP and will let you know.

Thanks Bill.

 

 

Put everything back together this morning and drove it to work.

Only had the opportunity to get up to ~65mph, but did several descent throttle second gear pulls.

Of course, no codes, no issues. . .

I did confirm that the VSS seems to be working just fine. . . no speedo issues and the cruise control works as it should.

Standy for updates, I will find somewhere to drive it faster on the way home from work.

 

Well....... got all the same "U" codes today while sitting in the driveway. . .

Cleared all of the codes and drove the rest of the morning without any more issues. 2 more ignition cycles with no issue.

So it does not seem to be speed related. . . thoughts?

 

U series DTCs can be confusing and do not necessarily mean anything specifically bad is happening. To me, they are an INDICATOR of something that happened during one of the modules communications checks. Unless you have a specific malfunction and there is a specific U series DTC for that module and the BCM I wouldn't much worry about those U series DTCs.

As long as you are driving without a specific problem happing, ENJOY the day!

Bill