Fault code P0755 – a step-by-step guide to diagnosing and fixing it

Error code P0755 is displayed and the check engine light is on - what does this mean?

The DTC P0755 is recognized by the OBD/EOBD system if there is a problem with the shift solenoid valve B of the automatic transmission. This trouble code relates to the transmission control module and may have slightly different definitions for different manufacturers, but basically refers to malfunctions of the 2-3 shift solenoid.

What causes can this error code have?

• Defective shift solenoid valve B (2-3 shift solenoid)
• Damaged or corroded wiring to the solenoid
• Loose or defective plug connections
• Low transmission oil level or contaminated ATF
• Clogged transmission oil filter
• Defective transmission control module (TCM)
• Mechanical problems in the valve body
• Internal transmission damage or wear

What symptoms occur in parallel with fault code P0755?

• Shifting problems: The automatic transmission shifts jerkily or irregularly between gears
• Shift blockage: The transmission gets stuck in a gear and does not shift any further
• Delayed shifting: Significant delay when changing gear, especially from 2nd to 3rd gear
• Check engine light: The check engine light is permanently illuminated
• Emergency running program: The transmission switches to safety mode with limited functionality
• Increased fuel consumption: Consumption increases due to inefficient gear changes

How can the problem with fault code P0755 be rectified?

• Repairing fault code P0755 requires a systematic approach to identify the exact cause.
• Check the transmission oil level and quality: Check ATF level and top up if necessary or change completely, also replacing the transmission filter at the same time
• Check electrical connections: Check all plug connections to the shift solenoid for corrosion, damage or loose contacts and repair them
• Replace shift solenoid valve B: Locate the defective 2-3 shift solenoid in the valve body and replace with a new original part
• Repair wiring: Identify damaged cables between TCM and solenoid and repair or replace professionally
• Diagnose transmission control unit: Test TCM with professional diagnostic technology and replace or reprogram if defective
• Overhaul the valve body: In the event of mechanical problems, remove the entire valve body, clean and replace defective components