P0490 2018 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 2018 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.
Code P0490 2018 GMC Sierra Description
What are the Possible Causes of the DTC P0490 2018 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 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 P0490 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.
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Frequently Asked Questions about P0490 2018 GMC Sierra Code
1. What does the OBDII code P0490 mean on a 2018 GMC Sierra?
P0490 indicates that the Exhaust Gas Recirculation (EGR) motor control circuit is experiencing a high voltage condition, meaning the EGR system is not functioning as expected.
2. What are the common symptoms of code P0490 in a 2018 GMC Sierra?
Symptoms may include a check engine light, reduced engine performance, rough idling, increased emissions, or a failure to pass an emissions test.
3. What causes the P0490 code to appear on a 2018 GMC Sierra?
Common causes include a faulty EGR valve, wiring issues such as damaged or corroded connections, a malfunctioning EGR motor, or a failed powertrain control module (PCM).
4. Can I drive my 2018 GMC Sierra with a P0490 code?
While the vehicle may still be drivable, it is not recommended as prolonged driving could lead to increased emissions, poor fuel economy, or damage to other components.
5. How do I diagnose the P0490 code on my 2018 GMC Sierra?
Diagnosis typically involves using an OBDII scanner to confirm the code, inspecting the EGR valve and wiring for damage, and testing the EGR motor and related circuits for proper voltage and continuity.
6. How can I fix the P0490 code on my 2018 GMC Sierra?
Repairs may include cleaning or replacing the EGR valve, repairing or replacing damaged wiring, or replacing the EGR motor or PCM if they are found to be faulty.
7. Does a dirty EGR valve cause the P0490 code on a 2018 GMC Sierra?
Yes, a dirty or clogged EGR valve can cause the P0490 code by restricting proper operation and triggering the high voltage condition in the control circuit.
8. How much does it cost to repair a P0490 code on a 2018 GMC Sierra?
Repair costs can vary, but replacing an EGR valve typically costs between $150 and $400, while wiring repairs or PCM replacements may increase the overall cost.
9. Can a bad PCM cause the P0490 code on a 2018 GMC Sierra?
Yes, a malfunctioning PCM can misinterpret or fail to control the EGR motor circuit, leading to the P0490 code, though it is less common compared to other issues.
10. Will clearing the P0490 code fix the issue on my 2018 GMC Sierra?
Clearing the code may temporarily turn off the check engine light, but the underlying issue needs to be addressed to prevent the code from returning.
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