B3647 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.

B3647 Code Symptoms :

The original multi-displacement system turned off opposite pairs of cylinders, allowing the engine to have three different configurations and displacements. B3647 code had an elaborate diagnostics procedure, including showing engine trouble codes on the air conditionning display. However, the system was troublesome, misunderstood by customers, and a rash of unpredictable failures led to the technology being quickly retired.

Diagnosis And Repairing B3647

B3647 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 B3647 code ?

• Engine Control Module (ECM)
• Failures of clutch motion/travel sensors.
• Exhaust tube
• Continuous oil flow to the VCT piston chamber

Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code B3647, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code B3647 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.