P0978
Shift Solenoid "C" Control Circuit Range/Performance
- Severity
- High
- Driving
- Drive only to a garage
The control circuit for shift solenoid "C" is electrically connected but not behaving as expected - the current drawn does not match what was commanded. This is the module's view of a solenoid that is not doing its job, so it is closely related to the shift solenoid "C" performance code and the two should be diagnosed together when both are stored.
Possible causes
- CommonSolenoid worn or sticking, drawing the wrong current
- CommonHigh resistance in the wiring or a corroded connector
- CommonDebris in the fluid restricting solenoid movement
- PossibleInternal transmission harness deteriorating
- PossibleLow or degraded fluid
- RareFailed control module driver
What you might notice
- Missing gears or a refusal to shift
- Harsh or delayed shifts
- Limp mode
- Check engine light on
What to check, in order
- Check the fluid level and condition first, and look for debris.
- Measure the solenoid resistance at the case connector against specification. A reading slightly outside tolerance is what produces this code rather than an outright electrical fault.
- Perform a voltage drop test on the circuit to find high resistance in the wiring.
- Note which gears are missing - the pattern narrows down which solenoid is genuinely at fault.
- Read all codes. A matching shift solenoid code describes the same component from the hydraulic side.
- Check whether an adaptation reset is specified after repair.
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 and control modules
P0900P0901P0902P0903P0904P0905P0906P0907P0908P0909P0910P0911P0912P0913P0914P0915P0916P0917P0918P0919P0920P0921P0922P0923P0924P0925P0926P0927P0928P0929P0930P0931P0932P0933P0934P0935P0936P0937P0938P0939P0940P0941P0942P0943P0944P0945P0946P0947P0948P0949P0950P0951P0952P0953P0954P0955P0956P0957P0958P0959P0960P0961P0962P0963P0964P0965P0966P0967P0968P0969P0970P0971P0972P0973P0974P0975P0976P0977P0978P0979P0980P0981P0982P0983P0984P0985P0986P0987P0988P0989P0990P0991P0992P0993P0994P0995P0996P0997P0998P0999