HomeTrouble CodesP2566

P2566 — Turbocharger Boost Control Position Sensor Circuit Intermittent

Manufacturer-specificPowertrain (engine & transmission)

The P2566 code indicates that the engine control module (ECM) has detected an intermittent or erratic signal from the turbocharger boost control position sensor, which monitors the position of the wastegate or boost actuator. This can lead to irregular turbo boost pressure, reduced engine performance, and possibly trigger other boost-related codes.

Symptoms

What causes it — most likely first

1. Faulty boost control position sensor

The sensor itself may fail internally, sending sporadic or out-of-range signals to the ECM.

2. Wiring or connector damage

Broken wires, corroded pins, or loose connections in the sensor circuit can cause intermittent readings.

3. Vacuum or boost line leaks

Leaky vacuum hoses feeding the wastegate actuator can change the mechanical position the sensor sees, creating an intermittent pattern.

4. Mechanical wastegate/actuator problem

A stuck or binding wastegate may cause the sensor position to change unexpectedly, triggering the code.

5. ECM software/hardware fault

Rarely, the ECM itself may misinterpret the sensor data due to a software bug or internal fault; this should be ruled out after the sensor and wiring are confirmed good.

6. Intake air leaks or charge pressure sensor issues

Unmetered air entering the intake can alter boost dynamics and indirectly affect the boost position sensor signal.

How it's diagnosed

  1. Retrieve all stored codes and freeze-frame data with a scan tool.
  2. Visually inspect the boost control position sensor, its connector, and the surrounding wiring for obvious damage or corrosion.
  3. Check the resistance and voltage of the sensor according to the manufacturer specifications (usually a 5‑V reference and a variable resistance output).
  4. Test the continuity and isolation of the sensor wiring harness, paying special attention to the signal, ground, and reference circuits.
  5. Inspect vacuum lines and boost hoses for cracks, disconnections, or leaks that could affect the wastegate actuator position.
  6. Operate the turbo (if safe) and monitor the sensor's live data to see if the signal drops out or fluctuates unexpectedly.
  7. If the above checks are normal, verify the ECM for any related fault codes and consider a reflash or replacement only after all other possibilities are eliminated.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Is the PCM (engine computer) usually at fault for P2566?

No. While the ECM can misinterpret the sensor data, the code is most often caused by the boost control position sensor itself or its wiring. PCM replacement is rarely needed and should only be considered after the sensor and wiring are proven good.

Can I still drive the vehicle with P2566?

Driving is possible, but you may experience intermittent loss of boost, reduced power, and poorer fuel economy. It is advisable to repair the issue promptly to avoid potential engine stress.

Will simply replacing the boost control position sensor fix the problem?

It often does, especially if the sensor is found to be out of spec or physically failed. However, the underlying cause (wiring, vacuum leaks, or mechanical issues) should also be addressed to prevent a recurrence.

Can a vacuum leak cause P2566?

Yes. A leak in the vacuum or boost lines that feeds the wastegate actuator can change the mechanical position that the sensor reports, leading to an intermittent signal and the P2566 code.