P093BHydraulic Accumulator Solenoid Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- The control circuit of the hydraulic accumulator solenoid reads low, usually a control wire shorted to ground or a coil with very low resistance. No manufacturer documents P093B publicly. GM covers the same fault on its surge accumulator solenoid with P171B: failed short to ground when circuit impedance drops below 0.5 Ohm in 32 of 40 samples, Type B with MIL after two trips. The accumulator holds pressurised fluid so clutches stay applied during an engine auto-stop, as GM's stop-start accumulator patent explains. P093A is the open-circuit fault, P093C the high fault and P093D the performance fault. A grounded control line can leave the valve permanently energised, and stop-start is typically switched off.
- What you may notice
- Warning light on (after repeated detection)
- Engine stop-start no longer active
- Harsh engagement after restart
- Likely causes
- LikelySolenoid control wire shorted to ground
- PossibleSolenoid coil shorted internally
- RareOutput driver in the control module failed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €150 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.