AutoCodes – RAM – U120C RAM

U120C RAM Code - Lost Brake Booster Signal

Quick Answer

The Diagnostic Trouble Code (DTC) sets when the Powertrain Control Module (PCM) doesn't receive a brake booster vacuum signal from the Anti-lock Brake System (ABS) Module over the Controller Area Network (CAN) C bus. Common causes include Faulty Brake Booster Pressure Sensor, Brake Booster Pressure Sensor harness is open or shorted, Brake Booster Pressure Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: U120C RAM indicates Lost Brake Booster Signal.
Common causes: Common causes include Faulty Brake Booster Pressure Sensor, Brake Booster Pressure Sensor harness is open or shorted, Brake Booster Pressure Sensor circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 741

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 03, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U120C RAM Description

OBDII Code U120C RAM - Lost Brake Booster Signal - AutoCodes.com — U120C RAM Code - Lost Brake Booster Signal

What does this mean?

What are the Possible Causes of the DTC U120C RAM?

Faulty Brake Booster Pressure Sensor
Brake Booster Pressure Sensor harness is open or shorted
Brake Booster Pressure Sensor circuit poor electrical connection
Faulty Anti-lock Brake System (ABS) Module

How to Fix the DTC U120C RAM?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U120C RAM code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the U120C RAM code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about U120C RAM Code

1. What are the common symptoms of OBDII code U120C RAM Lost Brake Booster Signal?

The common symptoms of this code include a loss of power brakes, a firm brake pedal, and the illumination of the ABS or brake warning light on the dashboard.

2. What could cause the OBDII code U120C RAM Lost Brake Booster Signal to appear?

The code U120C RAM typically appears due to a faulty brake booster sensor, damaged wiring or connectors in the brake booster circuit, or a malfunctioning powertrain control module (PCM).

3. How can I diagnose the cause of the U120C RAM Lost Brake Booster Signal code?

To diagnose the cause of this code, you can use a diagnostic scanner to retrieve and analyze the code, visually inspect the brake booster sensor and its connections, and perform a thorough check of the wiring harness for any damage or loose connections.

4. Can I continue driving my vehicle with the U120C RAM code related to the brake booster signal?

It is not advisable to continue driving your vehicle with the U120C RAM code related to the brake booster signal, as it can lead to a potential loss of power brakes, compromising your safety on the road.

5. How can I repair the U120C RAM Lost Brake Booster Signal code?

To repair the U120C RAM code, you may need to replace the faulty brake booster sensor, repair any damaged wiring or connectors in the brake booster circuit, and clear the code using a diagnostic scanner.

6. Are there any DIY tips for fixing the U120C RAM code at home?

While some basic troubleshooting steps can be performed at home, it is recommended to seek professional help for diagnosing and repairing the U120C RAM Lost Brake Booster Signal code to ensure the issue is addressed accurately and safely.

7. Is the repair for the U120C RAM code expensive?

The cost of repairing the U120C RAM code related to the brake booster signal can vary depending on the underlying cause of the issue, the extent of the repair needed, and whether you choose to do the repair yourself or seek assistance from a professional mechanic.

8. Can a U120C RAM code reset on its own?

In some cases, if the underlying issue causing the U120C RAM code is intermittent, the code may reset on its own after a certain number of drive cycles once the problem is resolved. However, it is recommended to diagnose and repair the issue promptly.

9. Will the U120C RAM code affect the overall performance of my vehicle?

Yes, the U120C RAM code related to the lost brake booster signal can affect the overall performance of your vehicle by potentially causing a loss of power brakes, which can impact your ability to brake effectively and safely.

10. How can I prevent the U120C RAM Lost Brake Booster Signal code from reoccurring?

Regular maintenance of your vehicle, including checking the brake system components, ensuring proper wiring connections, and addressing any warning lights promptly, can help prevent the U120C RAM code related to the brake booster signal from reoccurring.