What it means
The TCM detects an out-of-range overall transmission fluid pressure. Hydraulic supply pressure does not match the calibrated profile.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The transmission control module (TCM) uses pressure information to judge whether the hydraulic system is supplying the pressure needed for shifting and clutch operation. P0867 sets when overall transmission fluid pressure falls outside the calibrated operating profile, without identifying it simply as too low or too high.
Common causes
Most likely first.
- Transmission pump worn
- Transmission fluid level low
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Save freeze-frame data and check live transmission pressure and shift data to see when pressure moved outside its expected profile.
- Check the transmission fluid level and condition using the vehicle maker’s specified method, since low or degraded fluid can disrupt pressure.
- Inspect the transmission and cooler lines for leaks, and check accessible wiring and connectors for damage or poor contact.
- Compare scan-tool pressure readings with commanded pressure across operating conditions to determine whether the mismatch is persistent or tied to a particular shift.
- If the readings still disagree, have hydraulic pressure and pump operation tested against the manufacturer’s specification.
Common fixes
- Correct the transmission fluid level and repair any leak causing the loss.
- Repair damaged pressure-sensor or transmission wiring and connector faults found during inspection.
- Service contaminated or incorrect fluid as specified by the vehicle maker.
- Repair or replace a worn transmission pump if pressure testing confirms inadequate supply.
Can I keep driving?
Avoid towing, hard acceleration, and long trips while shifts are abnormal. Slipping or delayed engagement can worsen transmission damage; stop driving if the vehicle loses drive or shifts unpredictably.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.