What it means
The hydraulic accumulator solenoid reports a performance condition. Pressure storage charging cannot be commanded reliably.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The hydraulic accumulator solenoid controls pressure charging when commanded by the TCM. P093D sets when the solenoid's response or circuit performance does not match the expected behavior, even if the circuit is not simply open or consistently low or high.
Common causes
Most likely first.
- Actuator response slower than calibrated
- High-resistance contact
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
- Save freeze-frame data and review live accumulator solenoid commands alongside transmission symptoms to identify when the response is slow or inconsistent.
- Inspect the solenoid connector and harness for loose or corroded contacts and damage that could add resistance.
- Check control circuit continuity and contact resistance against the manufacturer's wiring information, including the connector terminals.
- If the circuit checks out, test solenoid response using the manufacturer's procedure and compare commanded operation with actual response.
- Repair the high-resistance connection or replace the confirmed slow or faulty solenoid, then verify normal response.
Common fixes
- Clean and secure a high-resistance or loose solenoid connector contact.
- Repair damaged or resistive wiring in the control circuit.
- Replace the accumulator solenoid if it responds more slowly than specified with a sound circuit.
- Clear the code and confirm the solenoid follows commands after repair.
Can I keep driving?
Avoid driving if shifts are delayed, harsh, slipping, or the transmission is in limp mode; slow accumulator solenoid response can disrupt pressure control and worsen wear. Keep driving to a minimum until the fault is repaired.
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.