The Traction Control and ABS lights are on and the dealer said that for the low prices of $3100 I can have EBCM replaced. That was $1400 for the part and $1700 for the labor, which I found excessive.
Ebay has them for close to $1000, and I'm willing to do the install myself. Does the EBCM require tech 2 or other special configuration equipment? If so, buying a T2 is still gonna be cheaper than the dealer.
EBCM replacement isn't particularly difficult and shouldn't be so expensive. After disconnecting the battery, the brake fluid pressure sensor needs to be disconnected, as well as the EBCM connector.
Then the car needs to be raised on at least jack stands.
The Electronic Brake Control Module is attached to the Brake Pressure Modulator Valve (BPMV) by four bolts; this combined unit resides on a bracket held by two bolts. After gently prying the two apart, (the seal can be reused if it isn't damaged, but I'd replace it anyway) the new EBCM is attached.
The final step is to run vehicle diagnostics with a Tech 2. No VIN programming is required.
You don't mention what year XLR this pertains to.
The EBCM for the '04 (P/N 18048955) sells for 656.26 and the '05-'09 (P/N 89060341) is priced @ $738.70. Both are available on the http://www.gmpartscenter.net/index.php?type=parts website. You can use the P/Ns to shop around at any of the other online GM OEM parts sites to find the best deal.