P0800
Transfer Case Control System (MIL Request)
- Severity
- Medium
- Driving
- Drivable — book it in
This is not a fault in itself. It is the transfer case control module asking for the check engine light to be switched on because it has stored a fault of its own. The real code sits inside the transfer case module and that is what has to be read - this one names no component and will clear when the actual fault is fixed.
Possible causes
- CommonA fault stored in the transfer case control module - this code only reports that one exists
What you might notice
- Check engine light on
- Four-wheel drive not engaging or disengaging
- Four-wheel drive warning light on
- Often no symptom at all
What to check, in order
- Read the transfer case control module, not just the engine module. Many basic scan tools only read the engine module, which is why this code so often appears alone with nothing to explain it.
- The real code will be stored in the transfer case module. Diagnose that one.
- Check the transfer case fluid level and condition while you are underneath.
- Do not replace parts on the strength of this code alone.
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