What P0894 means
P0894 reports slip of a transmission component, found by comparing speeds.
How the engine computer detects it
GM's 4L60-E applies it to the torque converter clutch: with lock-up commanded, slip between 100 and 550 rpm for 12.75 s on the third attempt in 4th gear sets it, type B with MIL after two trips; the module first freezes adaptation and raises line pressure. Lexus (Aisin AB60F) and Allison 1000 use it for a slipping shift element or low pressure and name the fluid level first. On the 4L60-E a cracked converter clutch PWM solenoid is a known cause.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Engine speed rises without matching acceleration, mostly when warm
- Shudder during lock-up
- Harsh shifts from maximum pressure, limp mode possible
Common causes
- Low, wrong or worn fluid Most likely
- Converter clutch PWM solenoid cracked or regulator bore worn (GM 4L60-E) Most likely
- Worn clutch plates or converter clutch lining Possible
- Pump not priming, cracked suction filter (Allison) Possible
- Control module software Less likely
How to diagnose P0894
- Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
- Inspect the parts involved: torque converter clutch, transmission clutches, transmission fluid, transmission pump, tcc pressure solenoid.
- Work through the causes above from most to least likely, cheapest checks first.
- Clear the code and drive a full drive cycle to confirm the repair held.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- 8
- Transmission
- 94
- Specific fault
Questions drivers ask
Can I drive with code P0894?
If the car shifts normally, drive gently to a shop. If it's stuck in one gear, slips, shifts harshly or won't move out of Park, don't drive it: have it towed.
Will my car pass an emissions inspection with P0894?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
Will P0894 clear by itself?
The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.