Powertrain
Definition only
Lights the check engine lamp
P2DE8: Cold Start Engine Coolant Bypass Valve D Stuck Open
Standardized SAE J2012 code · P2Dxx codes
What does P2DE8 mean?
During cold start, the engine coolant bypass valve D is stuck in the open position. Coolant bypasses the warm-up loop.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Common causes
- High Valve stuck in open position
- Medium Actuator failed
- Low Carbon or debris buildup preventing free movement
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P2DE8 on the same make and model first.
P2DE8 in the community
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