Throttle/Pedal Position Sensor Circuit High
The P2128 code indicates that the Engine Control Module (ECM) has detected a voltage signal from the throttle/pedal position sensor that is higher than the expected range. This sensor is critical for determining driver input and controlling throttle position. A high circuit condition typically points to a short to voltage, open ground, or a faulty sensor. This can lead to reduced engine power, poor acceleration, and potential safety concerns.
01. Most Common Causes
- Faulty throttle/pedal position sensor
- Short to voltage in sensor wiring
- Open ground circuit
- Corroded or damaged connector
- ECM failure (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Poor acceleration or hesitation
- Erratic idle or stalling
- Increased fuel consumption
03. Step-by-Step Diagnosis
Step 1: Connect an OBD2 scanner and confirm code P2128. Check for additional codes.
Step 2: Visually inspect the throttle/pedal position sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Using a multimeter, check the sensor reference voltage (typically 5V) and ground continuity. Compare signal voltage to manufacturer specs.
Step 4: If wiring is intact, test the sensor resistance and output voltage while moving the pedal/throttle. Replace if out of range.
Step 5: Clear the code and test drive. If code returns, check ECM for faults.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The vehicle may enter limp mode, limiting speed and acceleration, which can be dangerous in traffic. Have it diagnosed promptly.
How much does it cost to fix?▼
Typically $50-$150 for sensor replacement, plus diagnostic fees. Wiring repairs may add cost.