U1809 BMW Fault Code

Description:

Catalytic converters must be warm before they can work properly. On a cold start the PCM provides a rich mixture to keep the cold engine running.
All that extra fuel goes into the catalytic converter. But the exhaust isn't very hot, because, ah, the engine is pretty cold. GM has employed several strategies to fire up the catalytic converter quicker and reduce cold start emissions. One way is to use a secondary air pump that pumps outside air directly into the catalytic converter.

U1809 Code Symptoms :

If your U1809 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 U1809 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 U1809

U1809 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 U1809 code ?

• Air fuel ratio (A/F) Sensor 1 Bank 1 harness is open or shorted
• Faulty Fuel injector
• Dirty Oil
• 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 U1809, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code U1809 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.