B2021 BMW Fault Code

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.

B2021 Code Symptoms :

There are currently two main types of cylinder deactivation used today, depending on the type of engine. B2021 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 B2021

B2021 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 B2021 code ?

• EVAP system hose leaking
• Faulty Variable Camshaft Timing (VCT) position solenoid
• Air fuel ratio (A/F) Sensor 1 Bank 1 harness is open or shorted
• Open circuits caused by damage to wiring.

Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code B2021, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code B2021 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.