C0035 - Left Front Wheel Speed Circuit Malfunction

This is a common problem that affects many vehicles, especially those with anti-lock braking systems (ABS). In this article, I will explain what this code means, what causes it, what symptoms it may produce, how to troubleshoot it, and how to fix it. Let’s get started.

What is C0035 - Left Front Wheel Speed Circuit Malfunction?

C0035 is a diagnostic trouble code (DTC) that indicates a problem with the left front wheel speed sensor circuit. The wheel speed sensor is a device that measures the rotational speed of the wheel and sends a signal to the ABS module. The ABS module uses this information to adjust the brake pressure and prevent the wheels from locking up during braking.

The wheel speed sensor circuit consists of the sensor itself, the wiring, and the connectors. If any of these components are damaged, loose, corroded, or shorted, the circuit may malfunction and trigger the code C0035. The code may also be set if there is a mismatch between the left front wheel speed and the other wheels, which could indicate a faulty sensor or a mechanical problem with the wheel.

What causes C0035 - Left Front Wheel Speed Circuit Malfunction?

There are many possible causes for C0035, but some of the most common ones are:

• A faulty left front wheel speed sensor
• A damaged or broken wire in the left front wheel speed sensor circuit
• A damaged, cracked, corroded, or misaligned ABS reluctor ring
• A loose or corroded connector in the left front wheel speed sensor circuit
• A blown fuse or a bad relay in the left front wheel speed sensor circuit
• A mismatched tire size or pressure on the left front wheel
• A worn or damaged wheel bearing or hub on the left front wheel
• A faulty ABS module

What symptoms may C0035

Depending on the severity of the problem, C0035 may cause one or more of the following symptoms:

• The ABS warning light may illuminate on the dashboard
• The traction control system (TCS) or the stability control system (SCS) may be disabled or malfunctioning
• The vehicle may pull to one side during braking
• The braking performance may be reduced or uneven
• The vehicle may experience vibrations or noises from the left front wheel area

How to troubleshoot C0035 - Left Front Wheel Speed Circuit Malfunction?

To diagnose and fix C0035, you will need some basic tools and equipment, such as:

1. A scan tool that can read and clear DTCs
2. A digital multimeter that can measure voltage and resistance
3. A jack and jack stands that can safely lift and support the vehicle
4. A visual inspection mirror and a flashlight that can help you inspect hard-to-reach areas

The following steps will guide you through a basic troubleshooting procedure for C0035:

• Scan the vehicle with your scan tool and retrieve any stored DTCs. Note down any other codes that may be related to C0035, such as C0036 (Right Front Wheel Speed Sensor Circuit), C0040 (Right Rear Wheel Speed Sensor Circuit), or C0045 (Left Rear Wheel Speed Sensor Circuit). Clear all codes and test-drive the vehicle to see if C0035 returns.
• If C0035 returns, inspect the left front wheel speed sensor visually. Look for any signs of physical damage, such as cracks, breaks, or corrosion. Check the mounting bolts and make sure they are tight and secure. Check the wiring harness and connectors for any signs of damage, such as cuts, abrasions, burns, or corrosion. Repair or replace any damaged components as needed.
• If the visual inspection does not reveal any obvious problems, test the left front wheel speed sensor electrically. Disconnect the sensor connector and measure the resistance across the two terminals with your multimeter. Compare your reading with the specifications from your vehicle’s service manual. If the resistance is out of range, replace the sensor.
• If the resistance is within range, reconnect the sensor connector and measure the voltage across the two terminals with your multimeter. Spin the left front wheel by hand and observe your reading. You should see an alternating current (AC) voltage that varies with the wheel speed. If you do not see any voltage or a constant voltage, replace the sensor.
• If you see a normal voltage from the sensor, test the wiring and connectors in the left front wheel speed sensor circuit. Disconnect both ends of each wire in the circuit and measure the resistance with your multimeter. Compare your readings with the specifications from your vehicle’s service manual. If any wire shows an open circuit (infinite resistance) or a short circuit (zero resistance), repair or replace it.
• If all wires show normal resistance, test each connector in the circuit for continuity and corrosion. Clean any corroded terminals with electrical contact cleaner and a wire brush. Replace any damaged connectors as needed.
• If the wiring and connectors are good, test the fuse and the relay in the left front wheel speed sensor circuit. Locate the fuse and the relay in the fuse box and check their condition. Replace any blown fuse or bad relay as needed.
• If the fuse and the relay are good, test the ABS module for proper operation. Connect your scan tool to the vehicle and access the live data from the ABS module. Monitor the left front wheel speed sensor signal and compare it with the other wheel speed sensors. If the signal is erratic, missing, or incorrect, replace the ABS module.
• If the ABS module is good, check for any mechanical problems that may affect the left front wheel speed. Inspect the tire size and pressure and make sure they match the other tires. Inspect the wheel bearing and hub and make sure they are not worn or damaged. Replace any faulty components as needed.

How to fix C0035 - Left Front Wheel Speed Circuit Malfunction?

To fix C0035, you will need to replace or repair any faulty components that you identified during your troubleshooting process. Depending on the cause of the problem, you may need to replace one or more of the following parts:

1. The left front wheel speed sensor
2. The wiring or connectors in the left front wheel speed sensor circuit
3. The fuse or relay in the left front wheel speed sensor circuit
4. The ABS module
5. The tire, wheel bearing, or hub on the left front wheel

After you have fixed the problem, clear all codes with your scan tool and test-drive the vehicle to verify that C0035 does not return.

Conclusion

C0035 - Left Front Wheel Speed Circuit Malfunction is a common DTC that indicates a problem with the left front wheel speed sensor or its circuit. It can cause various symptoms, such as reduced braking performance, disabled traction or stability control, or dashboard warning lights. To diagnose and fix C0035, you will need to follow a systematic troubleshooting procedure that involves visual inspection, electrical testing, and mechanical inspection. By following this article, you should be able to diagnose and solve C0035 with ease.

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