The PCM/TCM has detected an issue with the Pressure Control Solenoid B, which regulates hydraulic pressure inside the automatic transmission. This solenoid ensures smooth gear shifts by controlling fluid flow to clutches and bands.

Possible Causes

1. Faulty Pressure Control Solenoid B (stuck, shorted, or open).
2. Dirty or low transmission fluid (causing improper pressure regulation).
3. Clogged transmission fluid passages.
4. Wiring issues – open/short circuits, corroded connectors.
5. Faulty Transmission Control Module (TCM) / PCM.
6. Mechanical transmission problems (valve body wear, internal damage).

Symptoms

1. Check Engine Light ON.
2. Harsh or erratic gear shifts.
3. Slipping transmission.
4. Transmission stuck in limp mode.
5. Overheating transmission.
6. Poor fuel economy.

Diagnosis Steps

1. Check transmission fluid – level, color, and smell (burnt fluid = overheating).
2. Inspect wiring/connectors at transmission harness.
3. Perform resistance test on Pressure Control Solenoid B (compare with spec).
4. Use scan tool to command solenoid ON/OFF and observe pressure changes.
5. Inspect valve body for blockages or wear if electrical parts test fine.

Possible Fixes

1. Replace Pressure Control Solenoid B.
2. Change transmission fluid & filter.
3. Repair/replace damaged wiring/connectors.
4. Clean or replace valve body if clogged.
5. Reprogram/replace TCM (if solenoid & wiring are fine).
6. Full transmission repair/rebuild (if internal damage).

About the Author
Harjeet Singh Sehmbi
Automatic Transmission Specialist·SEHMBI Automatic Transmission Repair Center
Harjeet Singh Sehmbi leads SEHMBI Automatic Transmission Repair Center, serving Mumbai and Bengaluru since 1980. He specialises in DSG, DCT, CVT, AMT, ZF and torque-converter gearbox diagnosis, rebuilding and replacement across Audi, BMW, Mercedes, Skoda, Volkswagen and Hyundai vehicles.