Pedal Correlation PDS1 and LPDS High
Your gas pedal sensors are sending signals that don't match each other or are both reading too high, like two speedometers disagreeing wildly. The engine computer detected this mismatch and won't trust your pedal input for safety reasons.
The ECM monitors two independent pedal position sensors (PDS1 and LPDS) to verify you're actually pressing the accelerator. Both sensors should produce proportional voltage signals that correlate with each other. When both signals read abnormally high or don't match, the ECU suspects sensor failure or mechanical binding.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| PDS1 and LPDS Correlation | Voltage signals within 10% of each other across pedal range | Both sensors >4.5V or correlation deviation >15% |
| Individual Sensor Voltage | 0.5V-4.5V proportional to pedal position | Either sensor stuck >4.5V or readings non-linear |
Code P1257 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P1257 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.