🚨 Diagnostic Profile
- Vehicle/Equipment Make: GENERIC
- Technical Description: Brake Booster Temperature Sensor B Circuit Low
This code is a Chassis code monitored by the Electronic Brake Control Module (EBCM) or the vehicle’s hydraulic brake booster/power steering control module. C0579 indicates that the module has detected a voltage signal from the ‘B’ temperature sensor circuit of the brake booster vacuum pump assembly that is lower than the expected calibrated range. This sensor monitors the internal operating temperature of the electro-hydraulic brake booster pump motor to prevent overheating and to regulate pump duty cycles. A ‘low’ voltage reading typically points toward a short-to-ground condition in the sensor wiring harness, a failed sensor internally, or corrosion at the connector pins feeding into the brake booster pump module. When this fault is active, the stability control and ABS systems may limit functionality or disable brake assist features as a protective measure, often triggering an illuminated ABS or Brake warning indicator on the dash.
🚨 Repair Difficulty Tier
- Difficulty Rating: Professional Only
This repair involves direct access to the hydraulic brake booster pump assembly, which is a safety-critical component requiring specialized bleeding procedures and module reset tools. A digital multimeter is required to check circuit resistance and voltage drop, but a professional-grade bi-directional scan tool is mandatory to clear the fault and verify brake system pressure parameters post-repair. Due to the safety implications of brake assist malfunction, this is not recommended as a DIY repair.
🛠️ Resolution Steps
- Step 1: Preliminary Inspection
Visually inspect the wiring harness connector at the brake booster pump assembly for signs of corrosion, melted insulation, or chafing against nearby chassis components. Check for any pinched wires near the pump mounting bracket, as vibration over time can cause the sensor circuit wire to ground out against the body of the pump housing. - Step 2: Diagnostic Verification
Using a scan tool, access the EBCM module and view live data for the Booster Temperature Sensor B PID to confirm if the voltage reading is stuck low or erratic. Back-probe the sensor connector with a digital multimeter (ignition on, engine off) to compare the actual sensor voltage against the value being reported by the module; a significant mismatch confirms a wiring fault rather than a sensor fault. - Step 3: Resolution & Reset Process
If the wiring tests within specification but the sensor data remains low, the internal temperature sensor integrated into the brake booster pump assembly will need to be replaced (this is often sold only as a complete pump/motor assembly unit). If a wiring short is found, repair the damaged section using proper soldering and heat-shrink techniques rated for the vehicle’s harness gauge. After the repair, use the scan tool to clear the stored fault code and perform a brake system bleed/calibration procedure to ensure proper hydraulic pressure before returning the vehicle to service.
📦 Parts, Labor, and Budget Estimates
- Required Components/Software: Brake Booster Pump Sensor/Assembly, OEM-level Bi-Directional Scan Tool, Wiring Repair Kit (if applicable)
- Average Component Price: $150 – $450 USD (sensor is often integrated into the pump assembly, raising cost)
- Estimated Labor Hours: 1.5 – 3.0 hours (includes diagnostic time and system bleeding)
- Total Estimated Budget: $300 – $700 USD