Throttle/Pedal Position Sensor Circuit High
The P2128 code indicates that the Engine Control Module (ECM) has detected a high voltage signal from the throttle/pedal position sensor circuit. This sensor is critical for determining driver input and controlling throttle position. A high voltage reading suggests a short to power, a faulty sensor, or wiring issues, which can lead to reduced engine power or limp mode.
1. Most Common Causes
- Faulty throttle/pedal position sensor
- Short to voltage in sensor circuit wiring
- Corroded or damaged connector
- ECM internal fault (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Poor acceleration or hesitation
- Erratic idle or stalling
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the throttle/pedal position sensor connector and wiring for damage or corrosion.
Step 3: Using a multimeter, check the sensor reference voltage (typically 5V) and signal voltage (should vary with pedal movement).
Step 4: Compare signal voltage to manufacturer specifications; if high (e.g., >4.5V), suspect a short to power.
Step 5: Test the sensor by disconnecting it and checking if voltage drops; if not, repair short in wiring.
4. 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.
How much does it cost to fix?▼
Typically between $50 and $150 for diagnosis and sensor replacement, but costs can vary if wiring repairs are needed.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.