What it means
The intermediate shaft speed sensor B reading is implausible against expected speed from gear ratio and input shaft speed.
At a glance
- Usually lights the check-engine light
How it works
Intermediate shaft speed sensor B reads the intermediate shaft’s rotation so the transmission control module can compare it with input speed and the expected gear ratio. This code sets when sensor B produces a signal that is present but implausible for the commanded ratio, which can result from a damaged tone wheel, an incorrect sensor gap, or sensor drift.
Common causes
Most likely first.
- Damaged tone wheel teeth produce missing pulses
- Sensor air gap drift
- Sensor element aged beyond calibration window
Symptoms
- Check-engine or transmission warning light on
- Harsh or delayed shifts
- Speedometer or gear indication may behave erratically
- Transmission may enter limp mode
How to diagnose it
- Review freeze-frame data and graph intermediate shaft sensor B alongside input speed and commanded gear to identify when the readings stop matching the expected ratio.
- Check for related transmission speed or ratio codes that could help distinguish a sensor B fault from another speed-signal problem.
- Inspect sensor B’s connector and harness for looseness, corrosion, chafing, or intermittent contact.
- Check sensor B’s mounting and air gap against the manufacturer’s specification.
- If mounting and wiring are sound, inspect the tone wheel for damaged or missing teeth and test sensor B for a drifting or weak signal.
Common fixes
- Repair a poor sensor B connector or damaged harness connection.
- Correct sensor B positioning or air gap to the manufacturer’s specification.
- Repair or replace a damaged tone wheel that produces missing speed pulses.
- Replace intermediate shaft speed sensor B if its signal fails testing despite correct mounting and wiring.
Can I keep driving?
Drive gently only as needed for diagnosis, and avoid towing or hard acceleration while the transmission’s ratio feedback is unreliable. Stop if shifts become severe, the transmission slips, or it enters limp mode; inaccurate speed feedback can cause poor shifting and additional transmission wear.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.