C0402 - Understanding DTC C0402: Common Causes and Solutions for 2010-2015 Chevrolet Equinox and GMC Terrain

Quick Answer

C0402 means: DTC C0402 indicates a malfunction in the brake switch B circuit, affecting brake light functionality and possibly other systems.

Fix: Check and replace faulty components Cost: $100 - $200 Time: 90-180 minutes

Can I drive with C0402? Immediate attention is recommended to ensure safe driving conditions.

Common Questions

What does C0402 mean and how does it affect my car?

DTC C0402 indicates a malfunction in the brake switch circuit, which is crucial for safety functions like brake lights and stability systems. If this code appears, you may experience issues like difficulty starting your vehicle or problems with your brake lights not functioning properly. These issues can lead to safety risks, so it's essential to address them promptly.

What are the most common causes of C0402 and how much does it cost to fix?

Common causes of C0402 include a faulty brake switch, wiring issues, or problems with the body control module. The average repair cost for replacing the brake switch ranges from $100 to $200, while wiring repairs can cost between $75 and $150. Addressing these issues timely can prevent further complications.

Can I drive my car with C0402 or should I stop immediately?

Driving with a C0402 code is not advisable as it can affect your brake lights and other safety systems. It's best to have your vehicle checked by a professional as soon as possible to avoid any risks of accidents or further damage.

How can I diagnose C0402 myself using GeekOBD APP?

Using the GeekOBD APP, you can perform a diagnostic scan to retrieve the C0402 code and any related codes. The app will provide you with freeze frame data that shows vehicle conditions at the time the code was triggered, which can help in diagnosing the issue effectively.

What vehicles are most commonly affected by C0402?

The C0402 code is frequently reported in models like the 2010-2015 Chevrolet Equinox and GMC Terrain. If you own one of these vehicles, it's essential to be aware of this code and its implications.

How can I prevent C0402 from happening again?

Regular maintenance checks, including inspecting the brake switch and wiring, can help prevent issues that might trigger the C0402 code. Keeping an eye on any warning lights and addressing them promptly can also mitigate future problems.

What is C0402?

DTC C0402 stands for 'Brake Switch B Circuit Malfunction,' indicating an issue within the brake switch circuit. This code is frequently encountered in vehicles like the 2010-2015 Chevrolet Equinox and GMC Terrain. The brake switch is crucial for safety as it controls various functions related to the brake system, including brake lights and traction control systems. When this code is triggered, it means that the vehicle's onboard diagnostics have detected a failure in the brake switch circuit. This failure can lead to several complications, such as the inability to start the engine, improper engagement of the brakes, or even the activation of other warning lights on the dashboard. If left unaddressed, this issue can compromise your vehicle's safety and performance, potentially leading to hazardous driving conditions. Therefore, understanding the implications of DTC C0402 is essential for maintaining your vehicle in safe operating condition. Regular inspections and prompt repairs can help mitigate the risks associated with this code, ensuring that your brake system functions correctly without any interruptions.

System: C - Chassis (ABS, Steering, Suspension)

Symptoms

Common symptoms when C0402 is present:

  • The check engine light illuminates, remaining on until the issue is resolved. This can be frustrating and often prompts drivers to seek diagnostic solutions.
  • Drivers may experience difficulty in starting their vehicle, as the brake switch is often needed to engage the starter, leading to intermittent starting issues.
  • Brake lights may fail to illuminate when the pedal is pressed, posing a danger to other drivers and increasing the risk of rear-end collisions.
  • Traction control warnings may appear, indicating a malfunction in the vehicle's stability systems, which can affect handling and safety.
  • Unexpected behavior of other electronic components, such as erratic operation of the cruise control system, may occur due to the brake switch circuit malfunction.

Possible Causes

Most common causes of C0402 (ordered by frequency):

  1. The most common cause of DTC C0402 is a faulty brake switch, which accounts for approximately 60% of cases. Over time, the switch can wear out or fail, leading to circuit malfunctions.
  2. Wiring issues, such as frayed or corroded connections in the brake switch circuit, can also trigger this code. This can happen due to environmental exposure or physical damage, with likelihood around 25%.
  3. Poor electrical connections can cause intermittent issues that trigger the C0402 code. Regular inspections and maintenance can help prevent these issues.
  4. Less common causes include issues with the vehicle's body control module (BCM), which may not interpret signals from the brake switch correctly, affecting brake system operations.
  5. In rare instances, software glitches in the vehicle's onboard computer can produce false codes, leading to unnecessary repairs and confusion.

C0402 Repair Costs

Cost Breakdown by Repair Type

Brake Switch Replacement

Replacing the faulty brake switch with an OEM part to ensure proper function.

  • Total: $100 - $200
  • Success rate: 90%
Wiring Repair

Repairing or replacing damaged wiring in the brake switch circuit.

  • Total: $75 - $150
  • Success rate: 85%
BCM Software Update

Updating the body control module software to resolve potential software issues causing false codes.

  • Total: $50 - $100
  • Success rate: 80%
Money-Saving Tips for C0402
  • Start with the most common and least expensive repairs first
  • Use GeekOBD APP to confirm diagnosis before replacing expensive parts
  • Consider preventive maintenance to avoid future occurrences
  • Compare prices for OEM vs aftermarket parts based on your needs
  • Address the issue promptly to prevent more expensive secondary damage

Diagnostic Steps

Professional C0402 Diagnosis Process

Follow these systematic steps to accurately diagnose C0402. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Start with a visual inspection of the brake switch and surrounding wiring

Step 1: Start with a visual inspection of the brake switch and surrounding wiring. Look for signs of damage, corrosion, or loose connections that could affect the circuit (5-10 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 2: Step 2: Use a diagnostic tool like the GeekOBD APP to read all stored codes

Step 2: Use a diagnostic tool like the GeekOBD APP to read all stored codes. This will help confirm the C0402 code and provide freeze frame data to understand the context of the fault (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 3: Step 3: Test the brake switch using a multimeter to check for proper function

Step 3: Test the brake switch using a multimeter to check for proper function. Monitor voltage and continuity to ensure the switch operates correctly (20-30 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 4: Step 4: Conduct a functional test of the brake system, including the operation of brake lights and related components after repairs are made

Step 4: Conduct a functional test of the brake system, including the operation of brake lights and related components after repairs are made. Clear the code to see if it reappears (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 5: Step 5: Perform a road test to ensure that all systems are functioning correctly and that no warning lights reappear (15-20 minutes)

Step 5: Perform a road test to ensure that all systems are functioning correctly and that no warning lights reappear (15-20 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.

Important Notes

  • Always verify the repair with GeekOBD APP after completing diagnostic steps
  • Clear codes and test drive to ensure the problem is resolved
  • Address underlying causes to prevent code recurrence

Real Repair Case Studies

Case Study 1: Brake Switch Replacement on 2013 Chevrolet Equinox

Vehicle: 2013 Chevrolet Equinox, 60,000 miles

Problem: Customer reported check engine light and malfunctioning brake lights.

Diagnosis: Diagnostic scan revealed C0402 code. Visual inspection showed a faulty brake switch.

Solution: Replaced the brake switch with an OEM part and tested the system.

Cost: $150 (Including part and labor)

Result: The vehicle's brake lights functioned properly after replacement, and the check engine light was cleared.

Case Study 2: Wiring Repair on 2012 GMC Terrain

Vehicle: 2012 GMC Terrain, 75,000 miles

Problem: Customer experienced intermittent starting problems and dashboard warning lights.

Diagnosis: Diagnostic scan revealed C0402 code. Inspection indicated damaged wiring in the brake switch circuit.

Solution: Repaired the wiring and replaced the brake switch.

Cost: $125 (Including part and labor)

Result: The vehicle started reliably, and warning lights were resolved after the repair.

Diagnose C0402

Use GeekOBD APP for professional diagnosis!

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  • Professional-grade analysis
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Code Information

Code: C0402
System: Chassis (ABS, Steering, Suspension)
Severity: HIGH
Category: Chassis Codes