Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
Separate the EBCM from the BPMV in order to inspect for corrosion or any other condition that may cause a poor connection at the pump motor connector. Refer to ELECTRONIC BRAKE CONTROL MODULE (EBCM) REPLACEMENT (W/ JL4) or ELECTRONIC BRAKE CONTROL MODULE (EBCM) REPLACEMENT (W/O JL4) and TESTING WIRING SYSTEMS FOR INTERMITTENT & POOR CONNECTIONS . If severe corrosion or other damage exists, the BPMV or the EBCM may need to be replaced.