B2891 BMW Fault Code

Description:

Intake Manifold Runner Control Malfunction (Stuck Open) The IMRC system is monitored for failure during continuous, key ON engine OFF or key ON engine running self-test. The test fails when the signal on the monitor pin is less than an expected calibrated range at closed throttle. IMRC monitor signal circuit shorted to BMW PWR GND or SIG RTN Damaged IMRC actuator Damaged PCM An IMRCM PID reading approximately near 1 volt at closed throttle may indicate a fault.

B2891 Code Symptoms :

There are currently two main types of cylinder deactivation used today, depending on the type of engine. B2891 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 B2891

B2891 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 B2891 code ?

• EVAP canister or fuel tank leaks
• Faulty Variable Camshaft Timing (VCT) position solenoid
• Incorrect fuel filler cap used
• Oil flow restriction in the oil passages or the VCT valve body

Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code B2891, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code B2891 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.