Circuit/System Verification

NOTE: Diagnose all other brake light DTCs or Symptoms prior to performing this diagnostic procedure.

Verify that DTC C0277 or C0278 is not set.
- If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
Ignition ON, observe the scan tool EBCM BPP parameter while applying and releasing the brake pedal. The reading should change between Applied and Released.
- If the parameter does not change between applied and release, replace the EBCM.
Replace the brake pressure modulator valve assembly.