P093C: Hydraulic Accumulator Solenoid Circuit High

What it means

The hydraulic accumulator solenoid reports a circuit high 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 is switched by the TCM to control pressure charging. P093C sets when the solenoid control circuit voltage is higher than expected, which may indicate a short to battery power, an open coil, or a poor connection.

Common causes

Most likely first.

1. Wire shorted to B+
2. Open coil
3. Connector pins corroded - high contact resistance

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

1. Record freeze-frame data and check for related transmission codes that could help identify when the accumulator solenoid circuit fault occurred.
2. Inspect the solenoid wiring and connector for damage, a wire shorted to battery power, corrosion, or loose terminals.
3. Check the control circuit for unwanted battery voltage and verify continuity using the manufacturer's wiring information.
4. Test the solenoid coil and connector contacts to determine whether an open coil or high-resistance connection is causing the high reading.
5. Repair the confirmed wiring or solenoid fault, then check that commanded solenoid operation no longer triggers the code.

Common fixes

• Secure or clean a loose or corroded solenoid connector.
• Repair wiring shorted to battery power in the accumulator solenoid circuit.
• Replace the solenoid if its coil is open.
• Clear the code and confirm normal circuit response after repair.

Can I keep driving?

Avoid driving if shifts are slipping, shuddering, harsh, or the transmission enters limp mode, because pressure charging may be unreliable and damage can worsen. Limit use until the solenoid circuit fault is repaired.