Shift solenoids are used by the ECU to force pressurized hydraulic fluid (a.k.a. the transmission fluid) to move different parts like clutches and gears. If there is an unusually high-voltage signal coming from the shift solenoid A control circuit, a P0974 DTC will be saved.
How Serious is the Code?
The P0974 diagnostic trouble code is one of the more serious OBD2 code that you can have. When a shift solenoid goes bad, you can experience a number of drivability problems that include usually hard shifts and a complete failure to change gears.
Symptoms of a P0974 include:
- Gear changes are usually harsh
- Transmission may not shift into gear
- Low or dirty transmission fluid
- Damaged connectors/wiring
- Faulty shift solenoid
How to Diagnose the Code?
The best way to start diagnosing a P0974 OBDII trouble code, is to first check the level and condition of the transmission fluid. If that checks out, the wiring and connectors should be checked for signs of damage and corrosion. After that, the valve body will have to be checked.
What Repairs Will Fix P0974?
- Service the transmission
- Replace or repair damage wiring/connectors
- Replace shift solenoid
- P0972 – Shift Solenoid “A” Control Circuit Range/Performance
- P0973 – Shift Solenoid “A” Control Circuit Low