AutoCodesGMC – P0490 2015 GMC Sierra

P0490 2015 GMC Sierra Code - Exhaust Gas Recirculation Motor Control Circuit High Voltage

Quick Answer

The Engine Control Module (ECM) supplies the Exhaust Gas Recirculation (EGR) valve with a 5 V reference circuit, a low reference circuit, an H-bridge motor directional control circuit, and a signal circuit. Common causes include Faulty Exhaust Gas Recirculation (EGR) Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation 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
P0490 2015 GMC Sierra indicates Exhaust Gas Recirculation Motor Control Circuit High Voltage.
Common causes
Common causes include Faulty Exhaust Gas Recirculation (EGR) Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation 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 302
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jun 19, 2022
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Code P0490 2015 GMC Sierra Description

The Engine Control Module (ECM) supplies the Exhaust Gas Recirculation (EGR) valve with a 5 V reference circuit, a low reference circuit, an H-bridge motor directional control circuit, and a signal circuit. The EGR position sensor provides a signal voltage that changes relative to the EGR position. The EGR position sensor information is transmitted between the EGR valve and the ECM on the signal circuit. The Mass Air Flow (MAF) sensor signal is used by the ECM to detect the proper amount of EGR flow. The ECM will close the EGR valve, then open the EGR valve to 100%. The ECM will then calculate the MAF difference and determine if the proper EGR flow has been detected. The Diagnostic Trouble Code (DTC) will be set when the ECM detects a short to voltage on the control circuit for greater than 2.5 s.
OBDII Code P0490 2015 GMC Sierra - Exhaust Gas Recirculation Motor Control Circuit High Voltage - AutoCodes.com
P0490 2015 GMC Sierra Code - Exhaust Gas Recirculation Motor Control Circuit High Voltage

What are the Possible Causes of the DTC P0490 2015 GMC Sierra?

  • Faulty Exhaust Gas Recirculation (EGR) Valve
  • Exhaust Gas Recirculation Valve harness is open or shorted
  • Exhaust Gas Recirculation Valve circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

How to Fix the DTC P0490 2015 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 P0490 2015 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 P0490 2015 GMC Sierra 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 P0490 2015 GMC Sierra Code

1. What does the OBDII code P0490 mean on a 2015 GMC Sierra?

P0490 indicates a "High Voltage" issue in the Exhaust Gas Recirculation (EGR) motor control circuit, suggesting improper operation of the EGR system.

2. What are the common symptoms of the P0490 code?

Symptoms may include the Check Engine Light turning on, reduced engine performance, rough idling, poor fuel efficiency, or increased emissions.

3. What causes the P0490 code in a GMC Sierra?

Common causes include a faulty EGR valve, damaged EGR motor, wiring or connector issues in the EGR circuit, or a malfunctioning Powertrain Control Module (PCM).

4. Can driving with the P0490 code damage my 2015 GMC Sierra?

Driving with this code for a short time might not cause immediate damage, but prolonged driving can lead to increased emissions, poor performance, and potential engine damage.

5. How can I diagnose the P0490 code?

Start by inspecting the EGR valve and motor for damage, check the wiring and connections for corrosion or breaks, and use a multimeter or scan tool to test the EGR circuit's voltage.

6. How do I fix the P0490 code on my GMC Sierra?

Repairs may include replacing the EGR valve, repairing or replacing damaged wiring, cleaning carbon deposits from the EGR system, or reprogramming/repairing the PCM.

7. Is the EGR valve always the problem with a P0490 code?

No, while the EGR valve is a common cause, wiring issues or a faulty PCM can also trigger this code.

8. How much does it cost to repair a P0490 code on a 2015 GMC Sierra?

Costs vary depending on the issue, but replacing the EGR valve typically costs $150–$400 for parts and labor. Wiring repairs or PCM reprogramming may cost more.

9. Can I clear the P0490 code without fixing the issue?

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

10. Does the P0490 code affect emissions testing?

Yes, the P0490 code can cause your vehicle to fail emissions testing due to improper EGR system function and increased exhaust emissions.

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