AutoCodes – Generic – P00C9

P00C9 Code - Fuel Pressure Regulator High Control Circuit Low Voltage

Quick Answer

High-pressure fuel is regulated by the high-pressure fuel pump actuator, which is a part of the high-pressure fuel pump. Common causes include Faulty High-Pressure Fuel Pump, High-Pressure Fuel Pump harness is open or shorted, High-Pressure Fuel Pump electrical circuit poor 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: P00C9 indicates Fuel Pressure Regulator High Control Circuit Low Voltage.
Common causes: Common causes include Faulty High-Pressure Fuel Pump, High-Pressure Fuel Pump harness is open or shorted, High-Pressure Fuel Pump electrical circuit poor 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 5,146

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 Jun 24, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P00C9 Description

High-pressure fuel is regulated by the high-pressure fuel pump actuator, which is a part of the high-pressure fuel pump. The high-pressure fuel pump actuator is a solenoid valve. The Engine Control Module (ECM) provides battery voltage on the actuator high control circuit and ground on the actuator low control circuit. Both circuits are controlled through output drivers within the ECM. When deactivated, both drivers are disabled. When activated, the high control circuit driver energizes the high-pressure fuel pump actuator, and the low control circuit driver Pulse-Width Modulates (PWM) the low control circuit to the ground. The ECM monitors the voltage on the circuits to detect a failure. The Diagnostic Trouble Code (DTC) will set if the ECM detects a short to ground in the high-pressure fuel pump actuator high control circuit.

OBDII Code P00C9 - Fuel Pressure Regulator High Control Circuit Low Voltage - AutoCodes.com — P00C9 Code - Fuel Pressure Regulator High Control Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P00C9?

Faulty High-Pressure Fuel Pump
High-Pressure Fuel Pump harness is open or shorted
High-Pressure Fuel Pump electrical circuit poor connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P00C9?

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 P00C9 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 P00C9 code?

Need more information on how to fix the P00C9 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P00C9 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P00C9 Buick — Fuel Pressure Regulator High Control Circuit Low Voltage
P00C9 Cadillac — Fuel Pressure Regulator High Control Circuit Low Voltage
P00C9 Chevrolet — Fuel Pressure Regulator High Control Circuit Low Voltage
P00C9 GMC — Fuel Pressure Regulator High Control Circuit Low Voltage

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 P00C9 Code

1. What are the common symptoms of OBDII code P00C9 (Fuel Pressure Regulator High Control Circuit Low Voltage)?

The common symptoms of this code may include rough idling, poor engine performance, loss of power, and potentially stalling.

2. What are the possible causes of OBDII code P00C9?

Possible causes of this code include a faulty fuel pressure regulator, issues with the fuel pump, wiring or connector problems, or a problem with the engine control module (ECM).

3. How can I diagnose the cause of OBDII code P00C9?

Diagnosing this code typically involves using a scan tool to check for any other related codes, inspecting the fuel pressure regulator and its wiring, testing the fuel pump, and checking for any loose or damaged connectors.

4. Can a dirty fuel filter trigger OBDII code P00C9?

Yes, a dirty fuel filter can restrict fuel flow and cause low voltage at the fuel pressure regulator, potentially triggering this code.

5. What should I do if I encounter OBDII code P00C9?

If you encounter this code, it is important to address it promptly to prevent potential engine damage. Consider seeking assistance from a qualified mechanic to properly diagnose and repair the issue.

6. Is it safe to continue driving with OBDII code P00C9 present?

It is not recommended to continue driving with this code present, as it can lead to poor engine performance and potentially cause further damage if left unresolved.

7. Can I reset OBDII code P00C9 and see if it returns?

While you can clear the code to see if it returns, it is important to address the underlying issue causing the code to prevent further problems.

8. How much does it typically cost to repair OBDII code P00C9?

The cost of repairing this code can vary depending on the cause of the issue, but it may involve replacing the fuel pressure regulator, repairing wiring, or addressing other related components.

9. Are there any DIY repair tips for OBDII code P00C9?

DIY repair tips may include checking and cleaning connectors, inspecting wiring for damage, and ensuring proper fuel system maintenance to prevent future issues.

10. Can a mechanic help me with diagnosing and repairing OBDII code P00C9?

Yes, a qualified mechanic will have the necessary tools and expertise to diagnose the issue accurately and recommend the appropriate repairs to resolve OBDII code P00C9.