Powertrain
Definition only
Lights the check engine lamp
P285A: Clutch B Pressure Disengagement Performance/Too Low
Standardized SAE J2012 code · P28xx codes
What does P285A mean?
Clutch B disengagement pressure is below the calibrated minimum. Clutch may not separate cleanly under load.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
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
Common causes
- High Hydraulic pump output pressure low
- Medium Pressure regulator characteristic drift
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P285A on the same make and model first.
P285A in the community
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