What it means
The transmission control module detects that more than one gear is engaged at the same time.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The transmission uses clutches, bands, and hydraulic controls to engage one gear at a time. The TCM compares gear and speed feedback with its commanded gear and sets P0893 when that information indicates that two or more gears are engaged together.
Common causes
Most likely first.
- Internal transmission or hydraulic fault
- Faulty transmission speed or gear feedback signal
Symptoms
- Transmission warning light or check-engine light may be on
- Abnormal shifting or loss of drive
- Transmission may enter a limited operating mode
How to diagnose it
- Record freeze-frame data and scan for related gear-ratio, speed-sensor, solenoid, and pressure codes before clearing anything.
- Check live data for commanded gear and transmission input and output speeds to see whether the apparent overlap occurs during a particular shift.
- Inspect transmission speed-sensor connectors and wiring for damage, loose pins, or contamination that could give the TCM false gear feedback.
- Check the transmission fluid level and condition using the vehicle's specified procedure, since low or contaminated fluid can disrupt hydraulic operation.
- If feedback signals are credible and the code returns, have the hydraulic controls and internal clutch or gear components evaluated against the manufacturer's diagnostic procedure.
Common fixes
- Repair a loose or damaged speed-sensor connector or wiring fault.
- Replace a speed sensor only if its signal fails testing.
- Correct the fluid level or service fluid if the manufacturer's procedure and condition call for it.
- Repair a failed hydraulic control component or internal transmission damage confirmed by diagnosis.
Can I keep driving?
Limit driving and avoid acceleration if shifts are abnormal, drive is reduced, or the transmission is in limited mode; continued operation can cause further internal damage. If the vehicle loses drive or behaves unpredictably, stop safely and arrange recovery.
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.