Redundant Sensor Error - Transmission Input/Output
There’s a discrepancy between the input and output sensors for the transmission system.
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What it means (plain English)
The truck's computer is seeing different readings from the sensors that measure the speed of the transmission's input and output. This could mean one of the sensors is faulty or there's a wiring problem.
What the computer is actually seeing
The computer anticipates matching speed readings from the input and output sensors. If the input sensor shows, say, 500 RPM and the output sensor shows 0 RPM, it'll trigger this code.
What a healthy reading looks like
Typically, input and output RPM readings should be within 10% of each other under normal operating conditions.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect wiring and connectors for both the input and output speed sensors; look for fraying, corrosion, or disconnection. If damaged, repair or replace as needed. Decision: Proceed to step 2 if connectors/wiring are good; otherwise, repair wiring first.
- 22. Use a scanner to check live data from both the input and output sensors. Document the RPM readings. Decision: If readings are within 10% of each other, look elsewhere; if they're too far apart, suspect faulty sensors.
- 33. If there's a discrepancy, replace the sensor that seems faulty (usually the one with no reading). Decision: Clear the code and see if it returns after a test drive.
Common causes
- Faulty input or output speed sensor
- Wiring issue between sensors and ECM
- Bad ground connection
- Faulty transmission control module (TCM)
- Oil contamination affecting sensor readings
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not advisable; it can lead to transmission issues and failure if not addressed.
Will this problem come back after fixing?
If the issue was with the sensors or wiring and you fix those, it generally won't come back.
Why does this code sometimes come with others?
These sensors often rely on similar wiring and systems, so if one is faulty, others can be too.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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