P0868
Transmission Fluid Pressure Low
- Severity
- Critical
- Driving
- Stop driving
Transmission fluid pressure is low. This matters more than most transmission codes: line pressure is what clamps the clutch packs together, and a clutch that is clamped weakly slips. A slipping clutch generates heat, and heat destroys the friction material quickly - a transmission driven for an hour with low pressure can need a rebuild that it would not have needed if it had been stopped.
Possible causes
- CommonLow fluid level - the cheapest and most common cause
- CommonExternal fluid leak
- CommonBlocked transmission filter
- CommonFailed pressure control solenoid
- PossibleWorn pump
- PossibleInternal leak past worn seals or a cracked drum
- PossibleFaulty pressure sensor reporting low when pressure is fine
What you might notice
- Slipping - engine speed rises without the car accelerating
- Delayed or no engagement when selecting drive or reverse
- Harsh, flaring shifts
- Limp mode
- Burnt smell
- Fluid puddle under the car
What to check, in order
- Stop driving and check the fluid level. Continuing to drive with genuinely low pressure is the difference between a repair and a rebuild, and the damage accumulates within minutes rather than weeks.
- Look underneath for a leak. A sudden low-pressure fault on a transmission that was fine yesterday is usually a leak, and topping up will get you home.
- Check the fluid condition. Burnt, dark fluid means damage has already begun.
- If the level is correct, do not keep driving on the assumption that the sensor is lying. Have the pressure tested with a gauge.
- Read all codes. Ratio or slip codes alongside this one confirm the clutches really are slipping.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Transmission
P0800P0801P0802P0803P0804P0805P0806P0807P0808P0809P0810P0811P0812P0813P0814P0815P0816P0817P0818P0819P0820P0821P0822P0823P0824P0825P0826P0827P0828P0829P0830P0831P0832P0833P0834P0835P0836P0837P0838P0839P0840P0841P0842P0843P0844P0845P0846P0847P0848P0849P0850P0851P0852P0853P0854P0855P0856P0857P0858P0859P0860P0861P0862P0863P0864P0865P0866P0867P0868P0869P0870P0871P0872P0873P0874P0875P0876P0877P0878P0879P0880P0881P0882P0883P0884P0885P0886P0887P0888P0889P0890P0891P0892P0893P0894P0895P0896P0897P0898P0899