C0035 Code (Symptoms, Causes, and How to Fix)

Last Updated on December 21, 2022

While many crafty motorists are familiar with powertrain-specific fault codes beginning with the “P” prefix, most are far less versed in the diagnosis and repair of chassis-related faults.

Faults of this nature typically involve a vehicle’s steering, suspension, and braking systems. Though somewhat less prevalent than many powertrain codes, chassis fault codes should be taken every bit as seriously.

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Some of the most common of all chassis-related fault codes are those which pertain to a vehicle’s individual speed sensors, and ABS (Anti-Lock Brake System). Luckily, the majority of such codes tend to be rather descript in nature, thereby providing those of a technical mindset with an excellent place to begin their diagnostic efforts.

One particular chassis fault code that tends to be among the most common of all encountered by the average motorist is DTC C0035. This code describes a speed sensor fault, which corresponds to a vehicle’s left-front speed sensor. As a result of this condition, the function and integrity of a vehicle’s ABS system can be negatively impacted.

Read on to learn more about DTC C0035, as well as how to address this issue, should it arise in the future.

What Does Code C0035 Mean?

OBD-II Trouble Code C0035 Description
Left Front Wheel Speed Sensor Circuit

Diagnostic Fault Code C0035 relates to a left-front wheel speed sensor circuit malfunction. Simply put, a vehicle’s control module has determined that feedback provided by a vehicle’s left-front speed sensor is incomplete, irrational, or out of range.

As a result of these inaccuracies, the affected vehicle’s management software often disables the ABS function as a whole, to prevent inadvertent and untimely ABS actuation.

Feedback relayed by a vehicle’s individual wheel speed sensors is vital, as it allows a vehicle’s control software to log and interpret the speed of one particular wheel, in relation to its counterparts.

As such, judgments can be made in a bid to predict wheel slip and wheel lockup, thereby allowing automated measures to be taken as a means of negating such issues.

Traditionally, wheel speed sensors have come in two distinct varieties, active and passive.

  • Passive sensors rely upon the creation of an AC voltage signal, which is magnetically induced when a vehicle’s wheels are in motion.
  • Active sensors are supplied with a constant input voltage/ground, which thereby allows a variable signal to be relayed on a secondary circuit to quantify speed.

In the case of either sensor, feedback is produced and registered as the unit detects individual magnetic pulses from a hub-mounted tone ring. The teeth of this tone ring are evenly spaced, thereby causing feedback pulsations to increase in frequency as wheel speed increases.

Related: Code P0500

Symptoms of Code C0035

what causes ABS light to come on?

Diagnostic fault code C0035 is often accompanied by a host of secondary symptoms, some of which tend to be more troubling than others. Learning to recognize these symptoms can prove quite helpful when attempting to address the issue at hand.

The following are several of the most common symptoms associated with DTC C0035.

  • Possible check engine light
  • Illuminated ABS warning light
  • Unexpected ABS actuation
  • Inaccurate wheel speed data

See Also: Why Is My Speedometer Not Working?

Causes of Code C0035

bad wheel speed sensor

Diagnostic fault code C0035 can be caused by one of several different underlying conditions, each of which must be addressed properly to reach a satisfactory conclusion.

Understanding these potential causes can provide you with a leg-up when striving to return your vehicle to service in the most expedited fashion possible.

The following are several of the most common root causes of DTC C0035.

  • Faulty left front wheel speed sensor
  • Damaged speed sensor wiring
  • Compromised ABS module
  • Damaged hub-mounted tone ring

Is Code C0035 Serious?

Diagnostic fault code C0035 is generally regarded as being quite serious in nature. This stems primarily from the fact that the presence of this code often renders a vehicle’s ABS system inoperable. While a vehicle’s standard brake function will be retained, stopping distances will be increased, under less than ideal circumstances.

Anti-lock braking is designed to provide rapid brake system pulsation, in a bid to prevent full wheel lockup. This is of significant value when forced to initiate a panic stop, or when attempting to stop rapidly in inclement weather. Anti-lock braking especially shines when stopping on ice or snow covered roads.

In any event, the root cause of a vehicle’s C0035 diagnostic fault code should be thoroughly diagnosed and repaired at the first available opportunity. Doing so will ensure that your vehicle’s ABS system is restored to full functionality.

If you do not feel comfortable tackling such repairs yourself, an appointment should be made with a trusted automotive service center as soon as possible.

How to Fix Code C0035

wheel speed (ABS) sensor

The following steps can be followed to assist in diagnosing and repairing the root cause of a vehicle’s C0035 diagnostic fault code. As always, factory specific service literature should be consulted for your particular vehicle, before attempting any such repairs.

#1 – Check For Additional DTCs

Before beginning the diagnostic process, be sure to check for the presence of any additional DTCs. Any such codes that are present should be thoroughly diagnosed before proceeding.

#2 – Perform Visual Inspection

Begin by carefully inspecting your vehicle’s left-front speed sensor and all associated wiring. The body of this sensor should not be damaged, nor should its connector. All pin connections within related connectors should be tight, and free of corrosion.

Additionally, all ABS wiring should be anchored in place, and free of breakage. ABS-specific wiring should not be repaired, but rather replaced in combination with the offending sensor itself.

#3 – Reset Sensor Air-Gap

If the prior inspection has presented no anomalies, the air-gap of the offending sensor should be checked. This can be done by simply applying light inward pressure to the body of the sensor itself while watching to see how deeply the sensor seats.

Ideally, this sensor should be seated within a nominal distance of the hub’s tone ring.

#4 – Verify Resistance

Resistance readings can also be taken at a vehicle’s speed sensor, to test integrity. Any reading taken should be compared to that specified by a vehicle’s manufacturer.

#5 – Take Functional Readings With Scan Tool or Oscilloscope

Finally, the integrity of the offending speed sensor should be verified through the use of an advanced scan tool or oscilloscope. The wave formations presented on such readings should be uniform, and without any stagnant periods in data delivery.

A failure during this phase of testing would likely indicate a faulty sensor.

Josh Boyd

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