Wheel Speed Sensor - Left Front Circuit
This code indicates a fault in the left front wheel speed sensor circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The computer isn't getting the right signals from the left front wheel speed sensor, which tells it how fast the wheel is spinning.
What the computer is actually seeing
The powertrain control module (PCM) expects to see a voltage signal indicating the wheel speed. Normally, this would be a square wave signal fluctuating between 0 volts (when the wheel is at rest) to around 5 volts (when the wheel is turning).
What a healthy reading looks like
The wheel speed sensor signal should fluctuate between 0.5V to 5V based on wheel speed, with a frequency of around 1Hz to 20Hz depending on vehicle speed.
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. Check the wiring harness and connectors for the left front wheel speed sensor for any visible damage, fraying, or corrosion.
- 2 - If you find damage, repair it and retest.
- 32. Verify the wheel speed sensor output using a multimeter. With the car in a safe position, measure the voltage at the sensor while spinning the wheel. You should see a varying voltage between 0.5V to 5V.
- 4 - If no signal or constant voltage is present, replace the wheel speed sensor.
- 53. Inspect the ground connection for the sensor to the PCM. Use the multimeter to check for continuity and the correct voltage. Ground should be less than 0.1 ohm resistance.
- 6 - If not correct, fix the ground issue and retest.
- 74. Clear the code and take the vehicle for a test drive. If the code returns, further diagnose the ABS module. This may require a scan tool to access ABS system data.
Common causes
- Damaged wiring or connectors in the wheel speed sensor circuit
- Faulty left front wheel speed sensor
- Poor sensor ground connection
- Corrosion or dirt in the connector
- Failed ABS module
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code present?
It's best not to drive the vehicle until the issue is fixed, as it can affect the ABS and traction control systems.
Will this code come back after clearing?
If the underlying issue isn't resolved, the code will likely return.
Why does this code pair with others like C1701?
These codes often indicate issues with multiple wheel speed sensors, as they all provide data to the ABS system.
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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