P0974Powertrain
Powertrain · SAE
Shift Solenoid A Control Circuit High
Meaning
The transmission control module has detected that the signal in the shift solenoid A (SSA) control circuit is above the expected maximum threshold: short to battery voltage or excessively high control voltage in the command circuit.
Common causes
- Short to battery (positive) in the SSA solenoid control wire
- Open circuit in the SSA solenoid return (ground) path
- SSA solenoid with open coil (infinite resistance) causing high voltage on the signal wire
- SSA control wiring shorted to supply voltage
- Internal TCM fault on the SSA solenoid driver producing a high signal
Symptoms
- Check engine or transmission warning light on
- Transmission in limp mode
- Abnormal or absent gear shifts in SSA-governed gears
- SSA solenoid does not switch (remains permanently energised or de-energised)
Severity
High: short to battery or open circuit in the SSA circuit prevents correct solenoid switching, impairing gear ratio selection.
What to do
- Measure SSA solenoid resistance with a multimeter (open circuit indicates a broken coil)
- Check for short to battery in the SSA control wire with a multimeter
- Verify the integrity of the SSA solenoid ground return path
- Inspect wiring and connectors for shorts to positive or open circuits
- Replace SSA solenoid or TCM depending on diagnosis