P0890
TCM Power Relay Sense Circuit Low
- Severity
- High
- Driving
- Drive only to a garage
The power relay sense circuit is stuck low - typically shorted to earth, or the relay not closing. The module sees the same relay state regardless of what it commands, so it cannot confirm that its supply is under control.
Possible causes
- CommonRelay stuck open or welded closed
- CommonWiring shorted to earth, or the relay not closing on the sense circuit
- CommonCorroded relay socket
- PossibleWater ingress into the fuse box
- RareFailed module input
What you might notice
- Transmission dead or in limp mode
- Battery flat after standing
- Check engine light on
What to check, in order
- Swap the relay with an identical one and see whether the fault follows it.
- Check whether the low reading persists with the relay removed. That separates the relay from the wiring.
- Inspect the socket for corrosion and heat damage.
- Check the fuse box for water.
- A relay welded closed keeps the module powered permanently and will flatten the battery. Do not leave the car standing with this fault.
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