🚨 Diagnostic Profile
- Vehicle/Equipment Make: GENERIC
- Technical Description: Brake Booster Solenoid Circuit Low
C0567 is a Chassis-level fault code monitored by the Electronic Brake Control Module (EBCM), which often works alongside the vehicle’s traction control and stability control systems. This specific code indicates that the control module has detected a lower-than-expected voltage signal on the circuit responsible for commanding the brake booster vacuum pump solenoid.
In vehicles equipped with an electro-hydraulic or vacuum-assisted brake booster system, the solenoid regulates vacuum pressure needed to provide proper brake pedal assist. A ‘Circuit Low’ condition typically points to a short to ground in the wiring harness, a failed solenoid coil (internal short), or a faulty EBCM driver output. Because this affects brake assist pressure management, the stability control and ABS systems may also log secondary codes or disable specific functions as a protective measure.
🚨 Repair Difficulty Tier
- Difficulty Rating: Intermediate
This repair requires a capable scan tool to read live ABS/EBCM data and a digital multimeter to test resistance and voltage drop across the solenoid circuit. While diagnosing the exact failure point requires some electrical troubleshooting experience, the physical repair (replacing a solenoid or connector) is manageable for an experienced DIYer with proper safety precautions regarding the brake system.
🛠️ Resolution Steps
- Step 1: Preliminary Inspection
Begin by visually inspecting the wiring harness and connector leading to the brake booster vacuum pump solenoid. Look for chafed wires, corrosion at the connector pins, or signs of melted insulation that could indicate a short to ground. Also inspect the vacuum pump assembly itself for physical damage or oil contamination that may have caused an internal electrical failure. - Step 2: Diagnostic Verification
Connect a scan tool capable of reading chassis/ABS codes and check live data for the solenoid circuit voltage. With the key on and engine off, use a digital multimeter to measure resistance across the solenoid terminals (disconnected from the harness) and compare it to manufacturer specifications. A reading significantly lower than spec confirms an internal short in the solenoid. Next, test the wiring harness independently for continuity to ground to rule out a chassis short. - Step 3: Resolution & Reset Process
If the solenoid itself tests faulty, replace the brake booster vacuum pump assembly or the solenoid component as per the specific vehicle’s service procedure. If a wiring short is found, repair or replace the damaged harness section using proper automotive-grade wire and heat-shrink connectors. After the repair, clear the stored code using the scan tool and perform a key-cycle test to confirm the ABS/EBCM module no longer detects the low-voltage fault. A test drive should be performed to verify the stability control and brake assist systems function normally with no return of the warning indicator.
📦 Parts, Labor, and Budget Estimates
- Required Components/Software: Brake booster vacuum pump/solenoid assembly, wiring harness repair kit (connectors, terminals, wire), digital multimeter, ABS-capable scan tool
- Average Component Price: $85 – $250 USD
- Estimated Labor Hours: 1.0 – 2.5 hours
- Total Estimated Budget: $160 – $450 USD