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P3256 BMW Fault Code

Check P3256 OBD Fault Code Reason
Description:

Output Shaft Speed sensor circuit intermittent failure The output shaft speed sensor signal to the PCM is irregular or interrupted.
Harness connector not properly seated Harness intermittently shorted, or open Harness connector damaged OSS sensor damaged, or not installed properly Verify harness and connector integrity Verify OSS sensor proper installation.

P3256 Code Symptoms :

See P3256 in engine

There are currently two main types of cylinder deactivation used today, depending on the type of engine. P3256 code for the pushrod design which uses solenoids to alter the oil pressure delivered to the lifters. In their collapsed state, the lifters are unable to elevate their companion pushrods under the valve rocker arms, resulting in valves that cannot be actuated and remain closed.

Diagnosis And Repairing P3256

P3256 OBD 2 code on vehicles with electronically controlled automatic transmissions, the 3-4 shift solenoid is responsible for actuating the hydraulic circuits to activate clutches or bands that change gears inside the automatic transmission.

How to fix P3256 code ?

See P3256 repair manual
  • EVAP system hose leaking
  • Faulty Mass Air Flow (MAF) sensor
  • Faulty front heated oxygen sensor
  • Erratic camshaft position due to low oil pressure

Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code P3256, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code P3256 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.

BMW Cars that meet P3256 error