What is an OBD2 code?

An OBD2 (On-Board Diagnostics) code is a diagnostic trouble code (DTC) generated by your vehicle's computer system when it detects a problem. These codes help identify specific issues with your vehicle's engine, transmission, emissions, or other systems.

How do I read OBD2 codes?

To read OBD2 codes, you'll need an OBD2 scanner. Plug it into your vehicle's OBD2 port (usually located under the dashboard), turn your key to the 'ON' position, and follow your scanner's instructions to retrieve the codes. Each code starts with a letter (P, B, C, or U) followed by four numbers.

What do the different types of OBD2 codes mean?

OBD2 codes are categorized by their first letter: P (Powertrain) for engine and transmission issues, B (Body) for interior systems like airbags, C (Chassis) for mechanical systems like brakes, and U (Network) for computer and module communication problems.

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Home » OBD2 Codes » U0128

Code U0128

Symptoms

• Parking brake warning light on

• Parking brake not functioning properly

• Intermittent parking brake operation

Common Causes

• Faulty parking brake control module

• Damaged wiring or connectors

• Faulty control module

Glossary

OBD-II: On-Board Diagnostics, a standardized system in vehicles for self-diagnosis and reporting

Control Module: An electronic device that controls various functions in the vehicle

Related Codes

• U0121

• U0122

Laymans terms

Your car's computer can't talk to the parking brake system. It's like when your phone can't connect to Wi-Fi.

Explanation

The vehicle's control module has lost communication with the parking brake control module.

Technical description

U0128 is a diagnostic trouble code that indicates a loss of communication with the parking brake control module. This can be caused by issues with the wiring, connectors, or the control module itself.

Diagnosis steps

• Check for other related codes

• Inspect wiring and connectors for damage

• Test the parking brake control module

Repair procedures

• Repair or replace damaged wiring/connectors

• Replace the parking brake control module

• Reprogram the control module if necessary

Tools required

• OBD-II scanner

• Multimeter

• Basic hand tools

Estimated repair cost

$150 - $500

Difficulty level

Moderate

Commonly affected vehicles

• Ford F-150

• Chevrolet Silverado

• Toyota Camry

Preventive measures

• Regularly inspect wiring and connectors

• Keep the vehicle's software updated

• Avoid harsh driving conditions

Error code type

Communication Error

User experience recommendations

• Do not ignore the warning light

• Get the vehicle checked by a professional

• Avoid using the parking brake until fixed

Warranty information

Check with the vehicle manufacturer for warranty coverage on control modules.

Historical data

U0128 has been a common issue in vehicles with electronic parking brake systems since their introduction.

Urgency level

Moderate – It should be addressed soon to ensure proper parking brake function.

Legal and safety notice

Ignoring this issue may lead to parking brake failure, which can be a safety hazard.

Testing conditions

• Vehicle parked on a flat surface

• Ignition in the 'on' position

Component location

The parking brake control module is usually located near the rear axle or integrated into the rear brake assembly.

FAQs

Q: Can I drive with code U0128?
A: It's not recommended as the parking brake may not work properly.

Q: How do I reset the U0128 code?
A: Fix the underlying issue and use an OBD-II scanner to clear the code.

Last updated: Jan 15, 2026 • Source: internal database

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