What it means
The control module detects a low electrical level in the shift solenoid A control circuit.
At a glance
- Usually lights the check-engine light
How it works
Shift solenoid A is an electrically operated valve that routes transmission fluid to help produce gear changes. The control module monitors the electrical level in solenoid A’s control circuit and sets P0973 when it is lower than expected. A short to ground or a poor connection can pull that circuit level down.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Capture freeze-frame data and check live transmission data for the conditions when the solenoid A circuit fault appeared.
- Inspect the solenoid A harness for chafing, especially where it can contact metal or other wiring.
- Check the solenoid A connector for corrosion, loose terminals, or poor pin contact that could lower the circuit signal.
- With the circuit tested according to the wiring diagram, check for a short to ground and inspect the control wire for damage.
- Test solenoid A and its circuit connections against the manufacturer’s specification before condemning the solenoid.
- Evaluate the transmission control module only if the ground short, wiring, connector, and solenoid checks pass.
Common fixes
- Clean or repair corroded or loose terminals at the solenoid A connector.
- Repair chafed insulation or a control wire shorted to ground.
- Replace shift solenoid A if it fails the specified electrical test.
- Repair or replace the transmission control module if circuit testing confirms an internal fault.
Can I keep driving?
A low solenoid A circuit can disrupt shifts even if the vehicle still moves; avoid hard acceleration and long trips, and stop if it slips or loses drive. Continued driving with abnormal shifts can increase transmission wear.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.