OBD Guide

P256A

Engine Idle Speed Selector Sensor/Switch Circuit/Open

P256A is an OBD-II diagnostic trouble code meaning: Engine Idle Speed Selector Sensor/Switch Circuit/Open. Common causes: broken wires in the sensor circuit, idle speed sensor/switch malfunction. Estimated repair cost: $17–56.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–56 (est.)

Symptoms

  • Unstable idle speed
  • Spontaneous change in engine speed
  • Stalls at idle
  • Check Engine light comes on
  • Increased or decreased idle speed

Causes

  • Broken wires in the sensor circuit
  • Idle speed sensor/switch malfunction
  • Poor contact in the sensor connector
  • Short circuit to ground or power
  • Malfunction of the engine control unit (rare)

How to Fix

  1. Check the integrity of the sensor wires and connectors
  2. Check sensor resistance (compare with factory specifications)
  3. Check the presence of power and ground at the sensor connector
  4. Replace idle speed sensor if necessary
  5. Reflash or replace the ECU if it malfunctions (extremely rare)

Related codes

Error P256A by Vehicle Brand

FAQ

What does the P256A code mean?

P256A is an OBD-II diagnostic trouble code that indicates: Engine Idle Speed Selector Sensor/Switch Circuit/Open

What causes a P256A error code?

The most common causes of P256A include: Broken wires in the sensor circuit; Idle speed sensor/switch malfunction; Poor contact in the sensor connector; Short circuit to ground or power.

How do I fix a P256A diagnostic trouble code?

To fix P256A: Check the integrity of the sensor wires and connectors. Check sensor resistance (compare with factory specifications). Check the presence of power and ground at the sensor connector. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P256A?

Yes, but get it checked soon

How much does it cost to fix P256A?

The estimated repair cost for P256A is $17–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat