🚨 Diagnostic Profile
Vehicle Make: BUICK
Technical Description: Secondary Vacuum Sensor Circuit
This code indicates an issue within the circuit responsible for monitoring the secondary vacuum reading used by the engine control module (ECM) to manage fuel delivery, turbocharger boost regulation, or EGR flow calculations. A fault here typically points to a wiring issue, a failed sensor, or a vacuum line leak affecting sensor accuracy.
🚨 Repair Difficulty Tier
Difficulty Rating: [Intermediate]
This repair requires the use of a diagnostic scan tool capable of reading live sensor data (PIDs) and a digital multimeter to test circuit continuity, resistance, and reference voltage. While not as high-liability as airbag or restraint repairs, it does require intermediate mechanical knowledge of vacuum systems and electrical circuit tracing to avoid misdiagnosis.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
Begin by visually inspecting the vacuum lines connected to the secondary vacuum sensor for cracks, disconnections, or collapsed tubing. Check the electrical harness and connector pins for corrosion, bent pins, or chafed wiring. Confirm the sensor is securely mounted and free of physical damage.
Step 2: Diagnostic Verification
Connect a scan tool to view live data from the secondary vacuum sensor. Compare the sensor’s voltage output at idle and under varying engine load to manufacturer specifications. Use a multimeter to verify the 5-volt reference signal, ground continuity, and signal return wire for voltage drops or opens. If readings fall outside normal operating range despite a confirmed good vacuum source, the sensor itself may be faulty.
Step 3: Resolution & Reset Process
If wiring and connections test correctly but sensor output remains abnormal, replace the secondary vacuum sensor with an OEM-spec replacement. After installation, clear the stored diagnostic trouble codes (DTCs) using the scan tool and perform a drive cycle to confirm the code does not return. In some cases, an ECM relearn or idle relearn procedure may be necessary to fully resolve the fault.
📦 Parts, Labor, and Budget Estimates
Required Components/Software: Secondary vacuum sensor, vacuum line/hose kit (if damaged), OBD-II scan tool with live data capability, digital multimeter.
Average Component Price: $45 – $120 for the sensor itself; vacuum hose kits typically range from $15 – $40.
Estimated Labor Hours: 0.5 to 1.5 hours for diagnosis and sensor replacement, depending on accessibility and whether additional relearn procedures are required.