AutoCodes – GMC – P12F8 GMC

P12F8 GMC Code - Cylinder Deactivation Exhaust Flow Valve Feedback Circuit Low Frequency Bank 2

Quick Answer

The cylinder deactivation exhaust flow control system consists of valves installed at the inlet of the muffler. Common causes include Faulty Cylinder Deactivation Exhaust Flow Valve, Cylinder Deactivation Exhaust Flow Valve harness is open or shorted, Cylinder Deactivation Exhaust Flow Valve 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: P12F8 GMC indicates Cylinder Deactivation Exhaust Flow Valve Feedback Circuit Low Frequency Bank 2.
Common causes: Common causes include Faulty Cylinder Deactivation Exhaust Flow Valve, Cylinder Deactivation Exhaust Flow Valve harness is open or shorted, Cylinder Deactivation Exhaust Flow Valve 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 1,098

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 Sep 12, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P12F8 GMC Description

The cylinder deactivation exhaust flow control system consists of valves installed at the inlet of the muffler. The exhaust flow control system is used to tune the exhaust note. The Powertrain Control Module (PCM) monitors the Cylinder Deactivation Exhaust Flow Valve. The PCM sets the OBDII code when the Cylinder Deactivation Exhaust Flow Valve is not to factory specifications.

OBDII Code P12F8 GMC - Cylinder Deactivation Exhaust Flow Valve Feedback Circuit Low Frequency Bank 2 - AutoCodes.com — P12F8 GMC Code - Cylinder Deactivation Exhaust Flow Valve Feedback Circuit Low Frequency Bank 2

What does this mean?

What are the Possible Causes of the DTC P12F8 GMC?

Faulty Cylinder Deactivation Exhaust Flow Valve
Cylinder Deactivation Exhaust Flow Valve harness is open or shorted
Cylinder Deactivation Exhaust Flow Valve circuit poor electrical connection

How to Fix the DTC P12F8 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 P12F8 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 P12F8 GMC code?

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Need Help with the Code?

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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 P12F8 GMC Code

1. What are the common symptoms of OBDII code P12F8 GMC?

- Common symptoms include rough idling, poor engine performance, decreased fuel efficiency, and potential illuminated Check Engine light.

2. What can cause the Cylinder Deactivation Exhaust Flow Valve Feedback Circuit Low Frequency Bank 2 code?

- Causes can include a faulty exhaust flow valve, wiring issues in the feedback circuit, a malfunctioning PCM, or a problem with the cylinder deactivation system.

3. How serious is the P12F8 GMC code?

- While the code itself may not cause immediate harm to the vehicle, it can lead to poor engine performance and reduced fuel efficiency if left unresolved.

4. How can I diagnose the Cylinder Deactivation Exhaust Flow Valve Feedback Circuit Low Frequency Bank 2 issue?

- Diagnosis typically involves using an OBDII scanner to read the code, inspecting the exhaust flow valve, checking the wiring for damage, and testing components related to cylinder deactivation.

5. Can I drive with OBDII code P12F8 GMC?

- It is generally not recommended to drive for an extended period with this code active, as it can affect the engine performance and fuel efficiency.

6. How can I repair OBDII code P12F8 GMC?

- Repairs may involve replacing the faulty exhaust flow valve, repairing damaged wiring, addressing issues with the cylinder deactivation system, or reprogramming the PCM.

7. Will resetting the Check Engine light resolve the P12F8 GMC code?

- Simply resetting the Check Engine light will not fix the underlying issue causing the code. It is important to diagnose and address the root cause of the problem.

8. Can a DIYer fix the Cylinder Deactivation Exhaust Flow Valve Feedback Circuit Low Frequency Bank 2 problem?

- Depending on the skill level and tools available, some DIYers may be able to address simpler causes like damaged wiring. However, more complex issues may require professional assistance.

9. How much does it cost to repair OBDII code P12F8 GMC?

- Repair costs can vary widely depending on the specific cause of the code, parts needed for replacement, labor rates, and whether the repair is done at a dealership or an independent mechanic.

10. How can I prevent OBDII code P12F8 GMC from recurring?

- Regular maintenance, addressing any related issues promptly, and ensuring proper functioning of the cylinder deactivation system can help prevent the code from recurring.