P0149 BMW Fault Code
Check P0149 OBD Fault Code ReasonLow 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.
P0149 Code Symptoms :
There are currently two main types of cylinder deactivation used today, depending on the type of engine. P0149 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 P0149
P0149 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 P0149 code ?
- Camshaft Position Sensor harness is open or shorted
- EVAP system hose leaking
- Faulty Fuel injector
- Ignition coils harness is open or shorted
Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code P0149, so consult the manual to locate the brake fluid reservoir.
Bear in mind that a low fluid level can set code P0149 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.
