Powertrain
Definition only
Lights the check engine lamp
P2D99: Starter/Generator Phase Y Current Circuit Intermittent/Erratic
Standardized SAE J2012 code · P2Dxx codes
What does P2D99 mean?
The current measurement on starter/generator phase Y drops out or jumps intermittently. Loose connector or vibration-sensitive sensor.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Common causes
- High Sensor connector not seated
- Medium Harness chafing intermittently shorts the wire
- Low Connector with intermittent contact under vibration
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P2D99 on the same make and model first.
P2D99 in the community
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