P309A BMW Fault Code

Description:

Low Speed Fuel Pump Primary Circuit Malfunction The PCM monitors the low speed fuel pump (LFP) primary circuit output from the PCM.
The test fails if: When the LFP circuit is commanded on (grounded), excessive current draw is detected on the BMW LFP circuit; or when the LFP circuit is commanded off, voltage is not detected on the LFP circuit (the PCM expects to detect VPWR voltage coming through the low speed fuel pump relay coil to the LFP circuit). Open or shorted low fuel pump (LFP) circuit Open VPWR to low speed fuel pump relay Damaged low speed fuel pump relay Damaged PCM An open circuit or short to ground can only be detected with the low speed fuel pump.

P309A Code Symptoms :

When you turn on the ignition, the Service Engine Soon or Check Engine P309A light should flash briefly, indicating that the OBD system is ready to scan your vehicle for any malfunctions. After this brief flash, the light should stay off while you drive as long as no problems are detected. If so, you'll be glad to know that your vehicle is equipped with an early warning system that could save you time, money, and fuel in addition to helping protect the P309A!

Diagnosis And Repairing P309A

P309A 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 P309A code ?

• Camshaft Position Sensor harness is open or shorted
• Camshaft advance mechanism binding (VCT unit)
• Engine Control Module (ECM)
• Faulty Fuel injector

Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code P309A, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code P309A on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.