P173B BMW Fault Code

Description:

The Transmission Fluid Pressure Switch allows the engine's control module (PCM) or Transmission Control Module (TCM) to use hydraulic fluid to engage the clutches in the transmission to allow for smoother shifting while driving. If the PCM or TCM detects an issue with the hydraulic clutch or the pressure switch, the BMW PCM or TCM will set code P173B

P173B Code Symptoms :

When you turn on the ignition, the Service Engine Soon or Check Engine P173B 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 P173B!

Diagnosis And Repairing P173B

P173B 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 P173B code ?

• Exhaust tube
• Camshaft advance mechanism binding (VCT unit)
• Faulty TCM or TCM programming
• Faulty select solenoid

Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code P173B, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code P173B on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.