AutoCodes – GMC – P2321 GMC

P2321 GMC Code - Ignition Coil 8 Control Circuit Low Voltage

Quick Answer

The ignition system on this engine uses ignition coils with integrated power transistors. Common causes include Faulty Ignition Coil 8, Ignition Coil 8 harness is open or shorted, Ignition Coil 8 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: P2321 GMC indicates Ignition Coil 8 Control Circuit Low Voltage.
Common causes: Common causes include Faulty Ignition Coil 8, Ignition Coil 8 harness is open or shorted, Ignition Coil 8 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 645

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 31, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P2321 GMC Description

The ignition system on this engine uses ignition coils with integrated power transistors. The Engine Control Module (ECM) controls the spark event for each cylinder through individual ignition coil control circuits. When the ECM commands the ignition control circuit On, electrical current flows through the primary winding of the ignition coil, creating a magnetic field. When a spark event is requested, the ECM commands the ignition control circuit Off, interrupting current flow through the primary winding. The collapsing magnetic field created by the primary winding induces a high voltage in the secondary winding, which is connected to the spark plugs. The Diagnostic Trouble Code (DTC) will be set when the control circuit commanded by the ECM state does not match the actual state.

OBDII Code P2321 GMC - Ignition Coil 8 Control Circuit Low Voltage - AutoCodes.com — P2321 GMC Code - Ignition Coil 8 Control Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P2321 GMC?

Faulty Ignition Coil 8
Ignition Coil 8 harness is open or shorted
Ignition Coil 8 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P2321 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 P2321 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 P2321 GMC code?

Need more information on how to fix the P2321 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P2321 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P2321 2014 GMC Sierra — Ignition Coil 8 Control Circuit Low Voltage
P2321 2015 GMC Sierra — Ignition Coil 8 Control Circuit Low Voltage
P2321 2016 GMC Sierra — Ignition Coil 8 Control Circuit Low Voltage
P2321 2017 GMC Sierra — Ignition Coil 8 Control Circuit Low Voltage
P2321 2018 GMC Sierra — Ignition Coil 8 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 P2321 GMC Code

1. What are the common symptoms of OBDII code P2321 GMC?

Common symptoms include rough engine idle, misfires, a decrease in engine performance, and potentially stalling.

2. What causes the OBDII code P2321 GMC to trigger?

The code P2321 is triggered when the Engine Control Module (ECM) detects low voltage in the control circuit of ignition coil 8.

3. How can I diagnose the issue related to OBDII code P2321 GMC?

Diagnosing the issue may involve checking the wiring connections to the ignition coil, testing the ignition coil itself, and inspecting the ECM for any potential faults.

4. Can a faulty ignition coil cause the OBDII code P2321 GMC?

Yes, a faulty ignition coil can lead to low voltage in the control circuit, triggering the P2321 code.

5. What are some repair tips for addressing OBDII code P2321 GMC?

Repair tips may include replacing the ignition coil, checking and repairing any damaged wiring, and resetting the ECM to clear the code.

6. Is it safe to continue driving with the OBDII code P2321 GMC present?

It is not recommended to drive with the P2321 code present, as it can lead to further engine issues and potential damage if left unresolved.

7. Can a DIY enthusiast fix the OBDII code P2321 GMC at home?

Depending on your skill level, you may be able to address the issue at home by following repair manuals or online tutorials. However, professional help may be necessary for accurate diagnosis and repair.

8. How much does it typically cost to fix OBDII code P2321 GMC at a mechanic's shop?

The cost of fixing the P2321 code can vary depending on the extent of the issue, but it may range from $100 to $300 for parts and labor.

9. Will resetting the OBDII system clear the P2321 code?

Resetting the OBDII system may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear.

10. Can a malfunctioning ECM cause the OBDII code P2321 GMC?

Yes, a malfunctioning Engine Control Module (ECM) can potentially cause low voltage in the ignition coil 8 control circuit, triggering the P2321 code.