P2784Transmission

Input/Turbine Speed Sensor A/B Correlation

P2784 means the transmission control module detected that the two input or turbine speed sensor signals do not agree, indicating a sensor or tone ring fault.

🚗 Not recommended for long. Mismatched turbine speed signals cause harsh shifts and limp mode.
HIGH
severity
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🎯 Top Causes, Ranked by Likelihood

#1Faulty turbine speed sensor A or B$100-$350
40%
One sensor reads incorrectly, breaking correlation.
#2Tone ring damage$300-$1000
25%
A damaged tone ring skews one signal.
#3Wiring fault$100-$350
20%
Intermittent wiring corrupts one signal.
#4TCM fault$500-$1200
15%
The reading circuit has failed.

🩺 Common Symptoms

💰 Repair Cost: DIY vs Shop

DIY Cost
$50-$400
Shop Cost
$150-$800

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose P2784

1Scan live data and compare both speed sensor readings
2Inspect wiring and connectors for both sensors
3Test each sensor output with a scope
4Inspect the tone rings for damage

❓ Frequently Asked Questions

Can I drive with P2784?
Only briefly. Mismatched speed signals cause harsh shifts and can force limp mode.
What does correlation mean?
The two turbine speed sensors should read the same; the code sets when they disagree.
How much to fix P2784?
Usually $150-$700 depending on which sensor and any wiring repairs.

🔗 Related Codes

P2765P2766P2767P0716
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