I've been trying to deal with the 'Service Brake System' warning. Everything seems to be OK with the pads and fluid. I've read the stuff from the search and cleaned up the ground on the frame. I wanted to check out the wheel sensors before I take it to the dealer for a possible EBCM flash. I read about checking them with a ohm meter etc. I don't have any manuals so I don't know how to even get to them. Can you explain the procedure to me. Can the sensors get contaminated to a point where they wont work?

you need to know the trouble codes that are stores in the ebcm. if you want to ohm out the sensors you just unplug them and use a dvom. should be around 1500 ohms varies a little with temperature.

I also found this:Document ID# 1307539
2003 Chevrolet Chevy K Silverado - 4WD


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ABS Telltale Illuminated, DTC C0550 Stored in History (Reprogram Electronic Brake Control Module (EBCM)) #03-05-25-003 - (Apr 22, 2003)
ABS Telltale Illuminated, DTC C0550 Stored in History (Reprogram Electronic Brake Control Module (EBCM))
2003 Chevrolet Express

2003 Chevrolet Silverado with GVW Rating over 8600 lbs

2003 GMC Savana

2003 GMC Sierra with GVW Rating over 8600 lbs

Condition
Some customers may comment on a permanent illuminated ABS telltale lamp. When checking for DTCs with the diagnostic scan tool, you may encounter DTC C0550 stored in history.

Cause
The HVAC blower motor, when the vehicle is keyed off, may generate sufficient electrical power during it's coast down period to cause a false C0550 code to set in the ABS module. The generated power created by the blower motor is of a "dirty" erratic nature, which cannot be correctly interpreted by the ABS module.

Correction
Reprogram the EBCM with the new service calibration, which was available from Techline starting April 14, 2003 on the TIS2000 version 4.0 or later. This calibration is an electronic calibration and is not available from GMSPO. DO NOT REPLACE the EBCM for this condition unless normal diagnosis identifies the module as the cause.

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

H2504*
EBCM Prom -- Reprogram
0.4 hr

*This is a unique labor operation number to be used only with this bulletin. It will not be published in the Labor Time Guide.




GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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Document ID# 1307539
2003 Chevrolet Chevy K Silverado - 4WD