AutoCodes – Buick – C158C Buick

C158C Buick Code - Steering Assist Hydraulic Pressure Out of Range

Quick Answer

The Active Hydraulic Assist Power Steering Control Module uses a pressure sensor to measure the hydraulic pressure in the left and right chambers of steering gear. Common causes include Faulty Steering Gear Pressure Sensor, Steering Gear Pressure Sensor harness is open or shorted, Steering Gear 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: C158C Buick indicates Steering Assist Hydraulic Pressure Out of Range.
Common causes: Common causes include Faulty Steering Gear Pressure Sensor, Steering Gear Pressure Sensor harness is open or shorted, Steering Gear 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 204

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 Jul 19, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code C158C Buick Description

The Active Hydraulic Assist Power Steering Control Module uses a pressure sensor to measure the hydraulic pressure in the left and right chambers of steering gear. The pressure signals are then used to determine the direction and rate of flow into each chamber to allow for steering assist. The Diagnostic Trouble Code (DTC) will be set when the Power Steering Control Module receives a signal that hydraulic pressure is out of range for 200ms.

OBDII Code C158C Buick - Steering Assist Hydraulic Pressure Out of Range - AutoCodes.com — C158C Buick Code - Steering Assist Hydraulic Pressure Out of Range

What does this mean?

What are the Possible Causes of the DTC C158C Buick?

Faulty Steering Gear Pressure Sensor
Steering Gear Pressure Sensor harness is open or shorted
Steering Gear Pressure Sensor circuit poor electrical connection
Faulty Power Steering Control Module

How to Fix the DTC C158C Buick?

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 C158C Buick 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 C158C Buick code?

Need more information on how to fix the C158C Buick code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C158C Buick code diagnosed by a professional: Find a repair shop in your area

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 C158C Buick Code

1. What does the OBDII code C158C mean on a Buick?

The code C158C indicates that the steering assist hydraulic pressure is out of range, meaning the system has detected an issue with the hydraulic pressure used in the power steering system.

2. What are the common symptoms of the C158C code?

Symptoms may include difficulty steering, a stiff steering wheel, reduced power assist, warning lights on the dashboard, or unusual noises from the power steering system.

3. What causes the C158C code to appear?

Possible causes include low or contaminated power steering fluid, a faulty hydraulic pressure sensor, a failing power steering pump, or damaged hydraulic hoses.

4. Can low power steering fluid trigger the C158C code?

Yes, low power steering fluid can cause insufficient hydraulic pressure, which may trigger the C158C code.

5. How do you diagnose the C158C code on a Buick?

Diagnosis typically involves checking the power steering fluid level and condition, inspecting the hydraulic pressure sensor, testing the power steering pump, and scanning for related codes.

6. Can I drive my Buick with the C158C code active?

Driving with this code is not recommended, as it may result in reduced or no power steering assist, making the vehicle harder to control and increasing the risk of an accident.

7. How is the C158C code fixed?

Repairs may include topping off or replacing the power steering fluid, replacing the hydraulic pressure sensor, repairing or replacing damaged hydraulic lines, or replacing the power steering pump.

8. How much does it cost to repair the C158C code?

The repair cost varies depending on the issue but typically ranges from $100 for a fluid replacement to $500 or more for a new power steering pump.

9. Can a faulty hydraulic pressure sensor alone cause the C158C code?

Yes, a faulty hydraulic pressure sensor can send incorrect readings to the vehicleâ€™s computer, triggering the C158C code.

10. How can I prevent the C158C code from occurring again?

Regularly check and maintain the power steering fluid, inspect the hydraulic system for leaks or damage, and address any steering issues promptly to prevent future problems.