🚨 Diagnostic Profile
Vehicle/Equipment Make: BUICK
Technical Description: Throttle Position (TP) Sensor 2 Circuit
This diagnostic trouble code indicates that the Powertrain Control Module (PCM) has detected an abnormal voltage condition on the signal circuit for the secondary Throttle Position sensor, which is typically integrated within the Electronic Throttle Control (ETC) assembly. This sensor works alongside TP Sensor 1 to provide redundant data on throttle blade angle, ensuring accuracy and safety in drive-by-wire systems.
🚨 Repair Difficulty Tier
[Intermediate]
This repair requires the use of a bi-directional scan tool capable of reading live sensor data (PIDs) and performing throttle body relearn procedures. While the physical replacement of the throttle body is mechanically straightforward, accurate diagnosis requires a digital multimeter to check wiring integrity and voltage reference signals. Improper calibration after replacement can cause drivability issues, so basic electrical diagnostic knowledge is necessary.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
Begin by visually inspecting the electrical harness connector at the throttle body assembly for corrosion, bent pins, or melted plastic. Check the wiring harness running from the throttle body to the PCM for chafing or rodent damage, as broken wires are a common cause of intermittent TP Sensor 2 faults. Ensure the throttle body itself is clean of carbon buildup, as this can sometimes cause voltage irregularities.
Step 2: Diagnostic Verification
Using a scan tool, access the live data stream and monitor the Throttle Position Sensor 1 and Sensor 2 percentages simultaneously; they should move in a mirrored, linear fashion as the throttle is manually manipulated (with the key on, engine off). If the values do not correlate or one sensor stays fixed at 0% or 100%, this confirms an internal sensor failure. Alternatively, back-probe the connector with a multimeter to verify the 5-volt reference signal and ground circuit are present and stable, ruling out a PCM wiring fault before condemning the part.
Step 3: Resolution & Reset Process
If wiring and reference voltages are confirmed to be intact, the resolution typically involves replacing the entire electronic throttle body assembly, as the TP sensors are generally not sold as separate serviceable components. After installation, the system will require a Throttle Body Relearn/Reset procedure using a scan tool to recalibrate the minimum and maximum position values to the PCM. Finally, clear the diagnostic trouble codes and perform a test drive to ensure the Check Engine Light does not return and idle quality is stable.
📦 Parts, Labor, and Budget Estimates
Required Components/Software: Electronic Throttle Body Assembly, OEM-level Scan Tool (for relearn procedure), Digital Multimeter (DMM).
Average Component Price: $150 – $350 for the throttle body assembly (dependent on specific engine size and trim level).
Estimated Labor Hours: 0.5 – 1.0 hour for diagnosis, plus 0.8 – 1.5 hours for replacement and relearn procedure (Total estimate: 1.3 – 2.5 hours).