AutoCodes – Lexus – C1939 Lexus

C1939 Lexus Code - Front Boosted Voltage

Quick Answer

The Active Stabilizer Converter supplies operating power to the Front Active Stabilizer Control ECU from the Front Active Stabilizer Control Actuator. Common causes include Faulty Active Stabilizer Converter, Faulty Battery (for active stabilizer), Active Stabilizer Converter harness is open or shorted. 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: C1939 Lexus indicates Front Boosted Voltage.
Common causes: Common causes include Faulty Active Stabilizer Converter, Faulty Battery (for active stabilizer), Active Stabilizer Converter harness is open or shorted.
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 918

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 Dec 05, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C1939 Lexus Description

The Active Stabilizer Converter supplies operating power to the Front Active Stabilizer Control ECU from the Front Active Stabilizer Control Actuator. Also, when the battery (for active stabilizer) voltage is low, the Active Stabilizer Converter charges it. If a problem occurs in the Front Active Stabilizer Control ECU, Active Stabilizer Converter, battery (for active stabilizer) and PIG power source circuit, DTCs C1939/32 and C193C/32 are stored.

OBDII Code C1939 Lexus - Front Boosted Voltage - AutoCodes.com — C1939 Lexus Code - Front Boosted Voltage

What does this mean?

What are the Possible Causes of the DTC C1939 Lexus?

Faulty Active Stabilizer Converter
Faulty Battery (for active stabilizer)
Active Stabilizer Converter harness is open or shorted
Active Stabilizer Converter circuit poor electrical connection
Faulty Front Active Stabilizer Control ECU

How to Fix the DTC C1939 Lexus?

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 C1939 Lexus 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 C1939 Lexus code?

Need more information on how to fix the C1939 Lexus code? Get Access to Factory Service Manuals

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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 C1939 Lexus Code

1. What does the OBDII code C1939 mean on a Lexus?

C1939 indicates an issue with the front boosted voltage circuit, often related to the adaptive suspension or electronic control system.

2. What are common symptoms of the C1939 code on a Lexus?

Symptoms may include suspension performance issues, a harsh or bumpy ride, warning lights on the dashboard, or reduced stability during driving.

3. What causes the C1939 code to appear?

Common causes include a faulty suspension control module, damaged wiring or connectors in the voltage circuit, or a malfunctioning height control sensor.

4. Can I drive my Lexus with the C1939 code active?

While the vehicle may still be drivable, the suspension system may not function correctly, leading to reduced ride quality and handling. It's best to address the issue promptly.

5. How do you diagnose the C1939 code on a Lexus?

Diagnosis involves using an OBDII scanner to confirm the code, inspecting the wiring and connectors in the suspension system, and testing the front boosted voltage circuit for irregularities.

6. What repairs can fix the C1939 code on a Lexus?

Repairs may include replacing a damaged suspension control module, repairing or replacing faulty wiring or connectors, or recalibrating the suspension system.

7. Is the C1939 code related to the air suspension system?

Yes, this code often relates to the electronic control of the air suspension or adaptive suspension system in your Lexus.

8. How much does it cost to fix the C1939 code on a Lexus?

Repair costs can vary, typically ranging from $200 to $1,000 depending on the specific issue, such as a module replacement or wiring repair.

9. Can a low battery cause the C1939 code on a Lexus?

A weak or failing battery can sometimes trigger voltage-related codes, but it's best to inspect the suspension system directly to confirm the root cause.

10. Does the C1939 code require reprogramming the suspension module?

In some cases, reprogramming or recalibrating the suspension control module may be necessary after repairs to clear the code and restore proper functionality.