Wheel Speed Sensor B Signal Range Performance Problem

Inside your vehicle's computer, the wheel speed sensor B is supposed to send a consistent voltage signal based on how fast the wheel is spinning. If the signal is too high or too low compared to what the computer expects, it triggers this code. This can happen because the sensor is dirty or damaged, or there’s an issue with the wiring.

The computer monitors the wheel speed sensor B's voltage output, which should fluctuate between 0.5V and 3.5V depending on speed. If the output is below 0.5V or above 3.5V for a certain duration during operation, it sets the C1021 code.

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.

1. 11. Inspect the wiring and connectors leading to wheel speed sensor B for any signs of damage or corrosion. If damaged, repair or replace.
2. 22. Check the voltage at the wheel speed sensor B connector with the key on, engine off. You should see around 5V coming to the sensor. If not, trace back to the ABS module for issues.
3. 33. With the vehicle in motion, measure the voltage output of the wheel speed sensor B. Use a multimeter to confirm it fluctuates between 0.5V and 3.5V. If not, replace the sensor.
4. 44. If the sensor checks out, use a scan tool to access ABS module data and look for any other fault codes that might give additional clues for further diagnosis.

• Faulty wheel speed sensor B
• Damaged wiring or connectors to sensor B
• Corrosion or dirt on the sensor
• Issues with the ABS control module
• Problems with the powertrain control module (PCM)

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