Transmission Input Speed Sensor
Transmission input speed sensor is out of range or malfunctioning.
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What it means (plain English)
The input speed sensor tracks how fast the engine's input shaft is spinning. If it's sending bad data, the transmission computer can't properly manage shifting and torque.
What the computer is actually seeing
The transmission control module is expecting input speed in a specific range, usually 0-3000 RPM. If the sensor reads outside this range or fails entirely, it triggers this fault code.
What a healthy reading looks like
Normal values for input speed sensor should be between 500 to 2500 RPM depending on the vehicle speed and gear selected.
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.
- 1Check the wiring and connectors for the input speed sensor for any damage or corrosion. Are they tight and clean? Decision: If yes, proceed. If no, repair or replace wiring/connector.
- 2Verify transmission fluid level and condition. Is it low or burnt? Decision: If yes, top off or replace fluid. If no, proceed.
- 3Measure the voltage at the input speed sensor connector. Is it within the range of 5-12 volts? Decision: If yes, proceed to the next step. If no, diagnose the power supply issue.
- 4Using a scan tool, check the readings from the input speed sensor. Does it give a valid RPM reading? Decision: If yes, the sensor may be fine, suspect the TCM. If no, replace the input speed sensor.
Common causes
- Faulty input speed sensor
- Wiring issues or bad connections
- Transmission fluid low or contaminated
- Faulty Transmission Control Module (TCM)
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It may be drivable but shifting could be erratic; it's best to fix soon to avoid further damage.
Will this code come back after clearing?
If the underlying issue isn't fixed, expect it to return after clearing the code.
Why does this code pair with SPN 5223?
SPN 5223 often relates to a related speed sensor fault, indicating issues in the same system.
Working a real vehicle right now?
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