🚨 Diagnostic Profile
- Vehicle/Equipment Make: GENERIC
- Technical Description: Brake Booster Temperature Sensor A/B Correlation
This Chassis code is monitored by the Electronic Brake Control Module (EBCM) and indicates a correlation fault between two temperature sensors (A and B) associated with the electro-hydraulic or vacuum-assisted brake booster pump assembly. The EBCM continuously cross-references the readings from these two sensors to ensure the booster pump motor is operating within a safe thermal range. When the module detects that Sensor A and Sensor B readings deviate from each other beyond a calibrated threshold—despite similar operating conditions—it flags this correlation error. This typically points to a wiring harness issue between the sensors and the module, a connector fault, or an internal failure within the booster pump housing itself. Because this sensor pair is responsible for preventing thermal overload of the brake assist pump, an unresolved fault can lead to the stability control or traction control indicators illuminating and the system temporarily reducing power assist to protect the pump motor.
🚨 Repair Difficulty Tier
- Difficulty Rating: Professional Only
This repair requires a bi-directional scan tool capable of reading live ABS module data streams and commanding specific booster pump tests, along with a digital multimeter for continuity and resistance checks on sensor wiring. Because the booster pump assembly is integrated into the brake hydraulic system, any disassembly carries safety and liability concerns requiring a certified brake technician.
🛠️ Resolution Steps
- Step 1: Preliminary Inspection
Visually inspect the wiring harness and connector pins leading to the brake booster pump assembly for corrosion, pinched wires, or loose connections. Check the mounting points of the pump housing for signs of overheating, melted plastic, or burnt wiring insulation, as this can indicate a long-standing thermal issue. - Step 2: Diagnostic Verification
Connect a scan tool capable of accessing the ABS/EBCM module and observe live data for both Temperature Sensor A and Sensor B simultaneously. Compare the real-time values under static (key-on, engine-off) and active (brake pump cycling) conditions. If the readings diverge significantly or one sensor remains static while the other fluctuates, use a digital multimeter to check resistance values against manufacturer specifications at the sensor connector with the harness disconnected. - Step 3: Resolution & Reset Process
If wiring or connector damage is found, repair or replace the affected harness section and reconnect securely. If both sensors test within an acceptable resistance range but still show correlation errors, the internal pump assembly sensor module itself likely requires replacement as a unit, since these sensors are often non-serviceable individually. After repair, clear the fault code using the scan tool and perform a bleed/initialization procedure for the brake booster pump as specified by the vehicle manufacturer, then verify no codes return after a full drive cycle with multiple braking events.
📦 Parts, Labor, and Budget Estimates
- Required Components/Software: Brake booster pump wiring harness or connector repair kit, OEM brake booster pump assembly (if sensors are integrated), bi-directional diagnostic scan tool with ABS module access
- Average Component Price: $150 – $450 USD (pump assembly) / $30 – $80 USD (harness/connector repair kit)
- Estimated Labor Hours: 1.5 – 3.0 hours
- Total Estimated Budget: $225 – $650 USD