AutoCodes – Generic – C0171

C0171 Code - TCS Pilot Valve Circuit Malfunction

Quick Answer

The Master Cylinder Isolation Valve, or TCS Prime Valve Solenoid circuits are supplied with battery power when the ignition is in the RUN position. Common causes include Faulty TCS Pilot Valve Solenoid, TCS Pilot Valve Solenoid harness is open or shorted, TCS Pilot Valve Solenoid 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: C0171 indicates TCS Pilot Valve Circuit Malfunction.
Common causes: Common causes include Faulty TCS Pilot Valve Solenoid, TCS Pilot Valve Solenoid harness is open or shorted, TCS Pilot Valve Solenoid 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 3,098

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 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C0171 Description

The Master Cylinder Isolation Valve, or TCS Prime Valve Solenoid circuits are supplied with battery power when the ignition is in the RUN position. The Electronic Brake Control Module (EBCM) controls the valve functions by grounding the circuit when necessary.

OBDII Code C0171 - TCS Pilot Valve Circuit Malfunction - AutoCodes.com — C0171 Code - TCS Pilot Valve Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC C0171?

Faulty TCS Pilot Valve Solenoid
TCS Pilot Valve Solenoid harness is open or shorted
TCS Pilot Valve Solenoid circuit poor electrical connection

How to Fix the DTC C0171?

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 C0171 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 C0171 code?

Need more information on how to fix the C0171 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C0171 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

C0171 Buick — TCS Pilot Valve Circuit Malfunction
C0171 Cadillac — TCS Pilot Valve Circuit Malfunction
C0171 Chevrolet — TCS Pilot Valve Circuit Malfunction
C0171 GMC — TCS Pilot Valve Circuit Malfunction
C0171 Pontiac — TCS Pilot Valve Circuit Malfunction
C0171 Saturn — TCS Pilot Valve Circuit Malfunction

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 C0171 Code

1. What are the common symptoms of OBDII code C0171 (TCS Pilot Valve Circuit Malfunction)?

- Common symptoms include poor engine performance, rough idling, decreased fuel efficiency, and the illumination of the check engine light.

2. What are the possible causes of OBDII code C0171?

- The code C0171 can be triggered by issues such as a faulty TCS pilot valve, wiring problems, a damaged connector, or a malfunctioning TCS control unit.

3. How can I diagnose the TCS pilot valve circuit malfunction?

- Diagnosing the issue involves using an OBDII scanner to retrieve the trouble codes, performing a visual inspection of the wiring and connectors, and testing the TCS pilot valve for continuity and proper operation.

4. What are some repair tips for fixing the TCS pilot valve circuit malfunction?

- Repair tips include checking and repairing any damaged wiring or connectors, replacing the faulty TCS pilot valve, ensuring proper connections, and clearing the trouble codes after completing the repairs.

5. Can I drive my vehicle with OBDII code C0171 (TCS Pilot Valve Circuit Malfunction)?

- It is not recommended to drive your vehicle with this code active, as it can lead to further engine damage and potential safety issues. It is best to address the issue promptly.

6. How much does it typically cost to repair OBDII code C0171?

- The cost of repairing this code can vary depending on the root cause of the issue, but it may range from $100 to $500, including parts and labor.

7. Can I reset the OBDII code C0171 without fixing the underlying issue?

- While you can clear the trouble code using an OBDII scanner, the check engine light is likely to reappear if the underlying problem is not addressed.

8. Are there any preventive measures to avoid OBDII code C0171 in the future?

- Regular maintenance of your vehicle, including checking the TCS system components, keeping the wiring in good condition, and addressing any warning signs promptly, can help prevent the recurrence of this code.

9. Is OBDII code C0171 a serious issue that requires immediate attention?

- While it may not cause immediate harm to your vehicle, ignoring this code can lead to decreased performance, reduced fuel efficiency, and potential engine damage over time. It is advisable to address it promptly.

10. Can a DIY enthusiast fix OBDII code C0171, or is it best left to professionals?

- Depending on your skill level and access to tools, a DIY enthusiast may be able to diagnose and repair the TCS pilot valve circuit malfunction. However, if you are unsure or uncomfortable with the process, it is best to seek the help of a professional mechanic.