AutoCodes – GMC – P0357 GMC

P0357 GMC Code - Ignition Coil 7 Control Circuit

Quick Answer

The ignition system on this engine uses ignition coils with integrated power transistors. Common causes include Faulty Ignition Coil 7, Ignition Coil 7 harness is open or shorted, Ignition Coil 7 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: P0357 GMC indicates Ignition Coil 7 Control Circuit.
Common causes: Common causes include Faulty Ignition Coil 7, Ignition Coil 7 harness is open or shorted, Ignition Coil 7 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 5,313

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 17, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0357 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 P0357 GMC - Ignition Coil 7 Control Circuit - AutoCodes.com — P0357 GMC Code - Ignition Coil 7 Control Circuit

What does this mean?

What are the Possible Causes of the DTC P0357 GMC?

Faulty Ignition Coil 7
Ignition Coil 7 harness is open or shorted
Ignition Coil 7 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0357 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 P0357 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 P0357 GMC code?

Need more information on how to fix the P0357 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0357 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P0357 2014 GMC Sierra — Ignition Coil 7 Control Circuit
P0357 2015 GMC Sierra — Ignition Coil 7 Control Circuit
P0357 2016 GMC Sierra — Ignition Coil 7 Control Circuit
P0357 2017 GMC Sierra — Ignition Coil 7 Control Circuit
P0357 2018 GMC Sierra — Ignition Coil 7 Control Circuit

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 P0357 GMC Code

1. What does the OBDII code P0357 mean on a GMC?

P0357 indicates a malfunction in the ignition coil "7" control circuit, which can affect engine performance.

2. What are the symptoms of a P0357 code on a GMC?

Symptoms may include engine misfires, rough idle, reduced power, poor fuel economy, and the Check Engine Light turning on.

3. What causes the P0357 code on a GMC vehicle?

Common causes include a faulty ignition coil, damaged wiring or connectors in the coil circuit, or a malfunctioning PCM (Powertrain Control Module).

4. How do I diagnose the P0357 code on my GMC?

Start by inspecting the ignition coil and its wiring for damage or corrosion. Use a multimeter to check for proper voltage and continuity in the circuit. Scan the PCM for additional codes.

5. Can I drive my GMC with a P0357 code?

Driving with this code is not recommended, as it can lead to increased engine misfires, reduced performance, and potential damage to the catalytic converter.

6. How do I fix the P0357 code on a GMC?

Repairs may include replacing the ignition coil for cylinder 7, repairing or replacing damaged wiring or connectors, or in rare cases, replacing the PCM.

7. How much does it cost to fix a P0357 code on a GMC?

Depending on the issue, repairs can range from $50-$300 for parts and labor, with ignition coils being the most common component replaced.

8. Where is ignition coil 7 located on a GMC?

The location of ignition coil 7 depends on the engine layout, but it will correspond to cylinder 7 in the firing order, which is typically on the driver's side near the rear of a V8 engine.

9. Can a bad spark plug cause the P0357 code on a GMC?

While the code specifically refers to the ignition coil circuit, a bad spark plug can cause similar symptoms and should be inspected as part of the diagnostic process.

10. Will clearing the P0357 code fix the issue on my GMC?

Clearing the code will turn off the Check Engine Light temporarily, but if the underlying issue isn’t resolved, the code will likely return.