P2747: Intermediate Shaft Speed Sensor B Circuit No Signal

What it means

The intermediate shaft speed sensor B produces no pulses while the shaft is known to be turning.

At a glance

• Usually lights the check-engine light

How it works

Intermediate shaft speed sensor B reads the rotation of its shaft, usually from a toothed target, and sends pulses to the transmission control module. The module sets P2747 when it expects the shaft to be turning but receives no pulses from sensor B, which can happen if the sensor has failed or its tone wheel has come loose or sheared.

Common causes

Most likely first.

1. Tone wheel sheared or rotating loose
2. Sensor failed completely

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

1. Save the freeze-frame data and compare live sensor B speed with input and other shaft speeds during a condition when the intermediate shaft should be turning.
2. Inspect sensor B's connector and wiring for looseness, damage, corrosion, or a broken signal wire.
3. Check whether sensor B's live reading stays at zero while the transmission is operating and the other speed readings change.
4. Test sensor B and its supply, ground, and signal circuit using the vehicle wiring diagram and manufacturer's specifications.
5. If the circuit and sensor test correctly, inspect the tone wheel for damage or looseness.

Common fixes

• Reconnect and secure sensor B's connector.
• Repair a broken or damaged sensor B wire or connector.
• Replace the failed intermediate shaft speed sensor B.
• Repair or replace the sheared or loose tone wheel.

Can I keep driving?

Avoid hard acceleration and towing; missing shaft-speed data can cause harsh shifts or limp mode and may make the gear indication unreliable. If the transmission slips, shifts unpredictably, or enters limp mode, stop driving and arrange recovery.