GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Impala 🢒 Brakes 🢒 Antilock Brake System 🢒 Vehicle Stability Enhancement System Inoperative

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The timelines for setting the pressure sensor DTCs associated with Stabilitrac time out. Before a pressure sensor fault can set sensor zeroing times out. Therefore no DTC is allowed to set. A Stabilitrac Disabled message comes ON after the vehicle has reached 48 km/h (30 mph).

Diagnostic Aids
    • The root cause of this symptom is a gap in the TRW supplier software thresholds for sensor zeroing versus fault detection. Before the sensor fault can set sensor zeroing times out. The pressure sensor faults will not run if the sensors are not zeroed. Therefore Stabilitrac never enables because the sensors do not zero and no DTC is allowed to set.
    • If brake pressure sensor VSES scan tool data is less than the specified value, call TAC for history driving scenarios of the "Stability Not Ready" message.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Antilock Brake System Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification
  1. With a scan tool. Verify no DTCS have set.
    2. ⇒If the DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  2. Observe the scan tool Brake Pressure Sensor Input voltage parameter in VSES scan tool data while the brake pedal is unapplied. The scan tool data value should be 0.7 volts.
    3. ⇒If voltage reads less than the specified value, refer to diagnostic aids and ABS Description and Operation.
    ⇒If voltage is equal to or greater than the specified value, test or replace the EBCM.

Repair Instructions
    •  Brake Pressure Modulator Valve Replacement
    •  Control Module References for EBCM replacement, setup, and programming

Repair Verification

Recheck the scan tool Brake Pressure Sensor Input voltage parameter in VSES scan tool data while the brake pedal is unapplied. The scan tool data value should be 0.7 volts.

⇒If voltage reads less than the specified value, system OK.
⇒If voltage still reads equal to or greater than the specified value, test or replace the brake pressure modulator valve (BPMV).