AutoCodes – GMC – P0615 2018 GMC Sierra

P0615 2018 GMC Sierra Code - Start Signal Circuit

Quick Answer

When the ignition switch is placed in the START position, a discrete signal is supplied to the Body Control Module (BCM) notifying it that the ignition is in the START position. Common causes include Faulty Starter Relay, Starter Relay harness is open or shorted, Starter Relay 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: P0615 2018 GMC Sierra indicates Start Signal Circuit.
Common causes: Common causes include Faulty Starter Relay, Starter Relay harness is open or shorted, Starter Relay 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 213

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 15, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0615 2018 GMC Sierra Description

When the ignition switch is placed in the START position, a discrete signal is supplied to the Body Control Module (BCM) notifying it that the ignition is in the START position. The BCM then sends a message to the Engine Control Module (ECM) that a crank has been requested. The ECM then verifies that the clutch pedal is depressed, or the transmission is in Park/Neutral. If it is, the ECM then supplies 12 V to the control circuit of the starter relay. When this occurs, battery voltage is supplied through the switch of the starter relay to the starter solenoid. The Diagnostic Trouble Code (DTC) will be set when the ECM detects improper voltage on the control circuit of the starter relay.

OBDII Code P0615 2018 GMC Sierra - Start Signal Circuit - AutoCodes.com — P0615 2018 GMC Sierra Code - Start Signal Circuit

What does this mean?

What are the Possible Causes of the DTC P0615 2018 GMC Sierra?

Faulty Starter Relay
Starter Relay harness is open or shorted
Starter Relay circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0615 2018 GMC Sierra?

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 P0615 2018 GMC Sierra 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 P0615 2018 GMC Sierra code?

Need more information on how to fix the P0615 2018 GMC Sierra code? Get Access to Factory Service Manuals

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 P0615 2018 GMC Sierra Code

1. What does the OBDII code P0615 mean on a 2018 GMC Sierra?

P0615 indicates an issue with the Start Signal Circuit, which involves the communication between the vehicle's starter system and the PCM (Powertrain Control Module).

2. What are common symptoms of the P0615 code on a 2018 GMC Sierra?

Common symptoms include failure to start, intermittent starting issues, or no response when turning the key or pressing the start button.

3. What causes the P0615 code on a 2018 GMC Sierra?

Possible causes include a faulty starter relay, damaged wiring or connectors in the start signal circuit, a defective ignition switch, or an issue with the PCM.

4. Can I drive my 2018 GMC Sierra with a P0615 code?

Driving may not be possible if the vehicle fails to start. Even if it starts intermittently, it’s recommended to address the issue promptly to avoid being stranded.

5. How is the P0615 code diagnosed on a 2018 GMC Sierra?

A technician will use a scan tool to verify the code, inspect the wiring and connectors in the start signal circuit, test the starter relay, and check the PCM for faults.

6. How do I fix the P0615 code on my 2018 GMC Sierra?

Repairs may include replacing the starter relay, repairing or replacing damaged wiring or connectors, replacing the ignition switch, or reprogramming/repairing the PCM if necessary.

7. What tools are needed to troubleshoot the P0615 code on a 2018 GMC Sierra?

Common tools include a digital multimeter to test electrical continuity, a scan tool to read and clear the code, and wiring diagrams for the start signal circuit.

8. Can a weak battery cause the P0615 code on a 2018 GMC Sierra?

Yes, a weak or failing battery can cause insufficient voltage to the start signal circuit, potentially triggering the P0615 code.

9. How much does it cost to repair the P0615 code on a 2018 GMC Sierra?

Repair costs can range from $50 to $300, depending on whether the issue is minor (e.g., repairing a wire) or requires component replacement such as the starter relay or ignition switch.

10. Is it necessary to clear the P0615 code after repairs?

Yes, after completing repairs, the code should be cleared using a scan tool, and the system should be retested to ensure the issue is resolved.