U1398 BMW Fault Code

Description:

The Transmission Range Sensor (also referred to as the PRNDL input an/or neutral safety switch) tells the transmission control module (TCM) an the engine control module (PCM) that the transmission is in park, reverse, neutral, drive, low, 2nd, 3rd etc. It is attached directly to the manual valve of transmission, so when the shift lever is moved from park to drive, the Transmission Range Sensor communicates this critical information to the above mentioned vehicle control module systems.

U1398 Code Symptoms :

There are currently two main types of cylinder deactivation used today, depending on the type of engine. U1398 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 U1398

U1398 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 U1398 code ?

• Engine Control Module (ECM)
• Faulty spark plug (s)
• Faulty spark plug (s)
• Faulty Crankshaft Position Sensor (POS)

Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code U1398, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code U1398 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.