AutoCodes – Chevrolet – P0490 2018 Chevrolet Silverado

P0490 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado - Exhaust Gas Recirculation Motor Control Circuit High Voltage - AutoCodes.com
P0490 2018 Chevrolet Silverado Code - Exhaust Gas Recirculation Motor Control Circuit High Voltage

What are the Possible Causes of the DTC P0490 2018 Chevrolet Silverado?

  • 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 2018 Chevrolet Silverado?

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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado code?

Need more information on how to fix the P0490 2018 Chevrolet Silverado 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 P0490 2018 Chevrolet Silverado Code

What does the OBDII code P0490 mean on a 2018 Chevrolet Silverado?

P0490 indicates a high voltage issue in the Exhaust Gas Recirculation (EGR) motor control circuit, which can affect the EGR system's operation.

What are the common symptoms of code P0490 on a 2018 Chevrolet Silverado?

Symptoms may include an illuminated check engine light, reduced fuel efficiency, rough idling, and possible engine performance issues.

What causes the P0490 code to appear on a 2018 Chevrolet Silverado?

Common causes include a faulty EGR valve, wiring issues such as damaged or corroded connectors, or a malfunctioning EGR control module.

Can driving with the P0490 code damage my 2018 Chevrolet Silverado?

While the vehicle may still run, ignoring the code can lead to long-term engine performance issues, increased emissions, and potential damage to the EGR system.

How do I diagnose the P0490 code on my 2018 Chevrolet Silverado?

Use an OBDII scanner to confirm the code, inspect the EGR valve and wiring for damage, and test the EGR motor for proper voltage and functionality.

What is the most common fix for the P0490 code on a 2018 Chevrolet Silverado?

The most common fix is replacing a faulty EGR valve, but it may also involve repairing or replacing damaged wiring or connectors in the circuit.

How much does it cost to repair the P0490 code on a 2018 Chevrolet Silverado?

Repair costs vary but typically range from $150 to $400, depending on whether the EGR valve, wiring, or other components need replacement.

Can a dirty EGR valve cause the P0490 code on a 2018 Chevrolet Silverado?

Yes, carbon buildup in the EGR valve can restrict movement and lead to high voltage readings, triggering the P0490 code.

Is it safe to clear the P0490 code without repairing the issue on a 2018 Chevrolet Silverado?

Clearing the code without addressing the cause may temporarily turn off the check engine light, but the issue will likely return and could worsen over time.

How can I prevent the P0490 code from occurring on my 2018 Chevrolet Silverado?

Regular maintenance, including cleaning the EGR valve and inspecting the wiring and connectors, can help prevent the P0490 code from appearing.

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