P121D BMW Fault Code

Description:

The issue covered by the bulletin involves a power steering noise/whine or fluid leak from the power steering pump, gear or high pressure side power steering hose during extreme low outdoor temperature operation.

P121D Code Symptoms :

If your P121D check engine light is illuminated, it's best to take it in for diagnostic testing, which can feel like a hassle. Because while the lights vary in appearance from vehicle to vehicle, all have the same basic meaning: There's a problem with the car's emissions system. The on-board diagnostics system P121D and engine control unit are in charge of monitoring a bunch of different , and if they get a reading that's a little out of whack, up pops the check engine light.

Diagnosis And Repairing P121D

P121D 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 P121D code ?

• Continuous oil flow to the VCT piston chamber
• Faulty Mass Air Flow (MAF) sensor
• Faulty select solenoid
• Incorrect Positive Crankcase Ventilation (PCV) hose connection

Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code P121D, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code P121D on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.