P0978Shift Solenoid C Control Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Range/performance fault in the drive circuit of shift solenoid C. GM's 2007 Allison 1000 table used it for an open SS3 circuit, but only while the commanded gear is not reverse trim, 5th or 6th; the table even prints the label Circuit Low beside an open-circuit test, an apparent typo. FCA lists P0978 among the four codes that the 2014–2016 9-speed transaxle set under old software when the range sensor harness had poor crimps. Ferrari's DCT bulletin uses it for a missing signal from the actuator 4 engage position sensor. Ford and GM six-speeds do not use it. Low/high are P0979/P0980, the current open code P097C.
- What you may notice
- MIL or transmission warning on
- Sudden neutral or default gear while driving
- Erratic or missing shifts
- Likely causes
- LikelyIntermittent high resistance at crimped harness terminals (FCA 9-speed)
- PossibleOpen coil of shift solenoid C (Allison-type usage)
- PossibleTransmission software that predates the manufacturer's fix
- RareFaulty driver stage in the transmission control module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €0 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.