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P2591 — Cruise Control Front Distance Range Sensor Left

Manufacturer-specificPowertrain (engine & transmission)

OBD-II code P2591 indicates a problem with the left front distance range sensor in the vehicle's cruise control system. This sensor helps maintain a safe following distance by detecting objects ahead, and a fault may disable adaptive cruise control or trigger warning lights.

Symptoms

What causes it — most likely first

1. Faulty left front distance range sensor

The sensor itself may fail due to internal electrical issues, physical damage, or contamination from dirt, debris, or moisture. This is the most common cause of P2591.

2. Wiring or connector issues in the sensor circuit

Damaged, corroded, or loose wiring or connectors between the sensor and the control module can disrupt signal transmission, triggering the code.

3. Misaligned or obstructed sensor

The sensor may be misaligned due to impact or improper installation, or its view may be obstructed by dirt, snow, or debris, affecting performance.

4. Faulty radar/lidar module (if integrated)

In systems where the distance sensor is part of a larger radar or lidar module, internal failures in the module can cause this code.

5. Software calibration or initialization issue

Incorrect calibration or a failed initialization process after sensor replacement or system updates may lead to false fault detection.

6. Control module (PCM/ECM or dedicated ACC module) failure

While rare, a failure in the control module responsible for processing sensor data could trigger this code. This is typically a last-resort diagnosis after other causes are ruled out.

How it's diagnosed

  1. Retrieve and document all stored trouble codes, including pending and history codes, to identify related faults.
  2. Visually inspect the left front distance range sensor for physical damage, misalignment, or obstructions. Clean the sensor lens if dirty.
  3. Check the wiring harness and connectors for damage, corrosion, or loose connections. Repair or replace as needed.
  4. Use a multimeter or oscilloscope to test the sensor's voltage, ground, and signal output according to the manufacturer's specifications.
  5. Verify proper sensor calibration or initialization procedures if the sensor or module has been recently replaced or updated.
  6. If all other causes are ruled out, test or replace the control module (PCM/ECM or dedicated ACC module) as a last step.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)
Related codesP2589 — Turbocharger Boost Control Position SeP2590 — Turbocharger Boost Control Position SeP2592 — Cruise Control Front Distance Range SeP2593 — Turbocharger Speed Sensor B CircuitP2594 — Turbocharger Speed Sensor B Circuit RaP2595 — Turbocharger Speed Sensor B Circuit Lo

Frequently asked

Is the engine computer (PCM/ECM) usually the cause of P2591?

No, the engine computer is rarely the cause of P2591. The issue is almost always related to the sensor itself, its wiring, or calibration. Replace the PCM only after all other potential causes have been thoroughly ruled out.

Can I drive with P2591 stored in the system?

While the vehicle may remain drivable, adaptive cruise control will likely be disabled. This could affect safety features that rely on the distance sensor, so it's recommended to diagnose and repair the issue promptly.

Why does my cruise control work sometimes but not others?

Intermittent issues are often caused by loose or corroded wiring, a failing sensor, or temporary obstructions (e.g., dirt or moisture) on the sensor. Thoroughly inspect the wiring and sensor for these conditions.

Do I need special tools to diagnose P2591?

Basic tools like a multimeter and an OBD-II scanner are sufficient for initial diagnosis. Advanced tools like an oscilloscope or manufacturer-specific scan tools may be needed for deeper testing of sensor signals or module communication.