Inspection and Verification
NOTE:
If a new ABS module or Hydraulic Control Unit (HCU) is installed, it must be calibrated. Refer to STABILITY/TRACTION CONTROL SYSTEM SENSOR CALIBRATION .
- Verify the customer concern.
- Verify the stoplamps operate correctly by pressing and releasing the brake pedal with the ignition switch in the OFF position. If the stoplamps do not operate correctly, refer to EXTERIOR LIGHTING article. If the stoplamps operate correctly, proceed to the next step.
- Verify that the PRNDL operates correctly on the Instrument Cluster (IC). If the PRNDL does not operate correctly, refer to INSTRUMENTATION, MESSAGE CENTER, AND WARNING CHIMES article. If the PRNDL operates correctly, proceed to the next step.
- Visually inspect for obvious signs of mechanical or electrical damage.VISUAL INSPECTION CHART
Mechanical Electrical - Wheel speed sensor ring
- Hydraulic Control Unit (HCU)
- Base brake system
- Brake booster vacuum hose
- Tire size
- Suspension components
- Steering components
- Restraints Control Module (RCM) installation
- Battery Junction Box (BJB) fuse(s):
- 9 (50A)
- 18 (20A)
- 25 (5A)
- ABS module
- Stoplamp switch
- Steering wheel rotation sensor (integral to the Electronic Power Assist Steering (EPAS) column)
- Brake fluid level switch
- Wiring, terminals or connectors
- Stability/traction control switch
- Wheel speed sensor
- RCM
- If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
- If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).
- If the scan tool does not communicate with the VCM:
- check the VCM connection to the vehicle.
- check the scan tool connection to the VCM.
- refer to MODULE COMMUNICATIONS NETWORK article, No Power To The Scan Tool, to diagnose no power to the scan tool.
- If the scan tool does not communicate with the vehicle:
- verify the ignition is ON.
- verify the scan tool operation with a known good vehicle.
- refer to MODULE COMMUNICATIONS NETWORK article to diagnose no response from the PCM.
- Carry out the network test.
- If the scan tool responds with no communication for one or more modules, refer to MODULE COMMUNICATIONS NETWORK article.
- If the network test passes, retrieve and record Continuous Memory Diagnostic Trouble Codes (CMDTCs).
- Clear the CMDTCs and carry out the self-test diagnostics for the ABS module.
- If the DTCs retrieved are related to the concern, go to ABS Module DTC Chart . For all other DTCs, refer to MULTIFUNCTION ELECTRONIC MODULES article.
- If no DTCs related to the concern are retrieved, GO to SYMPTOM CHART .
NOTE:
Make sure to use the latest scan tool software release.
NOTE:
The Vehicle Communication Module (VCM) LED prove out confirms power and ground from the DLC are provided to the VCM.
NOTE:
The vehicle must be at a complete standstill and on a level surface while carrying out the self-test. Any movement of the vehicle during the self-test may result in false DTCs being set.