If you’ve scanned your vehicle and discovered a C-code, you’re dealing with a Chassis Diagnostic Trouble Code (DTC). Unlike powertrain (P), body (B), or network (U) codes, C codes focus on the systems that keep your vehicle driving, braking, steering, and handling safely.

These systems include:

Anti-lock Braking Systems (ABS)
Electronic Stability Control (ESC/StabiliTrak)
Traction Control Systems (TCS)
Electronic Power Steering (EPS)
Four-Wheel Drive (4WD) systems
Electronic Suspension
Air Suspension
Electronic Parking Brakes
Wheel Speed Sensors
Transfer Case Controls
Differential Lock Systems
Chassis Control Modules

Whether you’re troubleshooting an illuminated ABS light, a Service 4WD warning, a traction control problem, or an electronic suspension fault, our growing library of C Code OBD-II guides provides detailed explanations, symptoms, causes, diagnosis procedures, repair costs, and preventative maintenance advice.

What Are C Codes?

OBD-II Diagnostic Trouble Codes are divided into four major categories:

P Codes – Powertrain
B Codes – Body
C Codes – Chassis
U Codes – Network Communication

A C Code is stored whenever a chassis-related control module detects an electrical, mechanical, or communication problem within a monitored system.

Unlike engine codes, chassis codes are often stored by modules such as:

Electronic Brake Control Module (EBCM)
Electronic Power Steering Module (EPS)
Transfer Case Control Module (TCCM)
Suspension Control Module
Electronic Parking Brake Module
Four-Wheel Drive Module
Chassis Control Module

Because many of these modules communicate over the CAN bus, multiple warning lights may illuminate simultaneously when a single fault occurs.

Common Symptoms of Chassis Codes

Depending on the system involved, a C-code may cause:

ABS warning light
Brake warning light
Traction Control light
Stability Control warning
Service 4WD message
Steering assist problems
Suspension warning light
Electronic parking brake warning
Reduced braking performance
Loss of traction control
Four-wheel drive engagement issues
Adaptive suspension faults

Some C-codes only illuminate a warning light, while others disable important safety features until repairs are completed.

Are C Codes Serious?

Many chassis codes affect critical safety systems.

Although most vehicles remain drivable, a stored chassis code may disable:

Anti-lock brakes (ABS)
Electronic Stability Control
Traction Control
Four-wheel drive operation
Adaptive suspension
Electronic steering assist
Electronic parking brake functions

Ignoring these problems can reduce vehicle safety, particularly during emergency braking or poor weather conditions.

What Causes Chassis Codes?

The most common causes include:

Failed wheel speed sensors
Damaged wiring harnesses
Corroded electrical connectors
Weak batteries
Charging system faults
Faulty ABS modules
Transfer case actuator failures
Steering angle sensor failures
Electronic suspension component failures
Poor ground connections
Failed actuators
Water intrusion
Worn electric motors
Internal module failures

Proper diagnosis should always begin with a professional scan tool capable of reading manufacturer-specific chassis modules, not just generic engine codes.

C Code Diagnostic Guides

Below you’ll find our complete library of C Code explanations. New guides are added regularly as we continue expanding the database.

C0035–C0050 Wheel Speed Sensor Codes

These codes cover the wheel speed sensors used by the ABS and traction control systems.

C0035 Code Explained – Left Front Wheel Speed Sensor Circuit
C0040 Code Explained – Right Front Wheel Speed Sensor Circuit
C0045 Code Explained – Left Rear Wheel Speed Sensor Circuit
C0050 Code Explained – Right Rear Wheel Speed Sensor Circuit

C0110–C0298 ABS & Electronic Brake Control Codes

These codes involve the ABS hydraulic unit, Electronic Brake Control Module (EBCM), pressure circuits, torque reduction requests, and related braking electronics.

Included guides:

C0300–C0387 Transfer Case & Four-Wheel Drive Codes

These guides cover transfer case electronics, encoder motors, front axle actuators, range switches, and shift system diagnostics.

Current articles include:

C0550–C0611 Electronic Control Module Codes

These articles focus on controller faults, module communication, VIN programming, and system disable conditions.

Available guides:

C0896–C0912 Voltage & Current Circuit Codes

Modern vehicles monitor actuator voltage and current continuously. These codes diagnose low voltage, high voltage, current performance, current circuit failures, and electrical performance issues.

Current guides include:

More voltage and actuator diagnostic guides are currently in development.

How We Diagnose C Codes

Every guide on Pro Street follows a professional diagnostic process that includes:

Reading all stored chassis module codes
Inspecting freeze-frame and live data
Verifying battery and charging system health
Performing voltage-drop testing
Testing wiring continuity
Inspecting connectors and grounds
Measuring actuator current draw when applicable
Verifying repairs with multiple drive cycles

This approach helps prevent unnecessary parts replacement and reduces repair costs.

Frequently Asked Questions

What is a C code?

A C code is an OBD-II Chassis Diagnostic Trouble Code used to identify problems with braking, steering, suspension, four-wheel drive, wheel speed sensors, and other electronically controlled chassis systems.

Can I drive with a C code?

Many C codes will not prevent the vehicle from driving, but important safety systems such as ABS, traction control, or stability control may be disabled. Diagnosis should be performed as soon as possible.

Do C codes turn on the Check Engine Light?

Usually not.

Most chassis faults illuminate the ABS, Brake, Stability Control, or Traction Control warning lights instead of the Check Engine Light.

Can a weak battery cause C codes?

Yes.

Many chassis control modules are sensitive to battery voltage. A weak battery or failing alternator can trigger multiple chassis DTCs simultaneously.

Do I need a professional scan tool?

For most C codes, yes.

Basic OBD-II scanners often cannot communicate with ABS, suspension, transfer case, or steering modules. A scan tool capable of reading manufacturer-specific chassis modules is recommended.

Why Trust Pro Street?

Every diagnostic guide on Pro Street is written specifically for automotive enthusiasts, DIY mechanics, and professional technicians. Rather than simply listing a definition, our articles explain:

What the code actually means
Why it occurs
Common symptoms
Root causes
Professional diagnostic procedures
Estimated repair costs
Frequently asked questions
Preventative maintenance tips

Our goal is to help you diagnose the problem correctly the first time.

More OBD-II Resources

Looking for other diagnostic trouble codes?

Browse our complete code libraries:

Powertrain (P) Codes
Body (B) Codes Explained –
Chassis (C) Codes
Network (U) Codes

Or visit the complete OBD-II DTC hub:

https://my.prostreetonline.com/dtc-obdii

C Code OBD-II Codes Explained: Complete Chassis Diagnostic Trouble Code (DTC) List