P2784
Input/Turbine Speed Sensor A/B Correlation
The two input or turbine shaft speed sensors A and B do not agree within tolerance. Either sensor may be drifting or missing pulses.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Damaged tone wheel teethCommon
- One sensor drifts in air gap or amplitudePossible
Parts involved
- Input Shaft Speed Sensor A
- Input Shaft Speed Sensor B
- Tone Wheel
P2784 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.