AutoCodes – GMC – C158C GMC

C158C GMC 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 GMC 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.

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Code Popularity 893

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

What does this mean?

What are the Possible Causes of the DTC C158C GMC?

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 GMC?

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 GMC 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 GMC code?

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

Need Help with the Code?

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Information for Specific GMC Models

C158C 2014 GMC Sierra — Steering Assist Hydraulic Pressure Out of Range
C158C 2015 GMC Sierra — Steering Assist Hydraulic Pressure Out of Range
C158C 2016 GMC Sierra — Steering Assist Hydraulic Pressure Out of Range
C158C 2017 GMC Sierra — Steering Assist Hydraulic Pressure Out of Range
C158C 2018 GMC Sierra — Steering Assist Hydraulic Pressure Out of Range

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 GMC Code

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

C158C indicates that the Steering Assist Hydraulic Pressure is out of range, meaning the vehicle's electronic control system has detected an issue with the hydraulic pressure used for power steering.

2. What are the common symptoms of code C158C in GMC vehicles?

Symptoms include difficulty steering, a stiff or unresponsive steering wheel, reduced power steering assist, and an illuminated check engine light or service power steering warning.

3. What causes the C158C code to appear in GMC vehicles?

Common causes include a faulty power steering pressure sensor, low or contaminated power steering fluid, damaged hydraulic lines, or issues with the power steering pump.

4. Can I still drive my GMC if code C158C is present?

Driving with code C158C is possible but not recommended, as reduced or no steering assist can make the vehicle harder to control, especially at low speeds or in emergencies.

5. How can I fix the C158C code on my GMC?

Repairs may involve inspecting and replacing the power steering pressure sensor, flushing and refilling the power steering fluid, repairing hydraulic lines, or replacing the power steering pump.

6. How do I diagnose the cause of code C158C in my GMC?

Start by checking the power steering fluid level and condition, inspecting for leaks in hydraulic lines, and using a scan tool to monitor the power steering pressure sensor's data for irregularities.

7. Can low power steering fluid trigger code C158C on a GMC?

Yes, low or contaminated power steering fluid can cause insufficient hydraulic pressure, leading to the C158C code.

8. How much does it typically cost to fix code C158C on a GMC vehicle?

Costs vary depending on the issue, ranging from $100â€“$200 for a fluid flush to $500â€“$1,000+ for replacing the power steering pump or repairing significant hydraulic system damage.

9. Is a faulty power steering pressure sensor a common cause of code C158C?

Yes, a malfunctioning power steering pressure sensor is a frequent cause of this code, as it may send incorrect pressure readings to the control module.

10. Can ignoring the C158C code cause further damage to my GMC vehicle?

Yes, ignoring the code can lead to increased wear on the steering components and potential safety issues due to loss of steering assist. Prompt diagnosis and repair are recommended.