AutoCodes – GMC – P0496 GMC

P0496 GMC Code - Evaporative Emission System Flow During Non-Purge

Quick Answer

The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Common causes include Faulty EVAP Canister Vent Valve, Faulty EVAP Canister Purge valve, Plugged EVAP canister condition. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means: P0496 GMC indicates Evaporative Emission System Flow During Non-Purge.
Common causes: Common causes include Faulty EVAP Canister Vent Valve, Faulty EVAP Canister Purge valve, Plugged EVAP canister condition.
Severity: Low - monitor the vehicle and repair when practical.
Can I drive?: The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

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Code Popularity 63,986

How popular is this code, among other codes? Medium

Repair Importance Level

Low (Monitor) (1 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Sep 13, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code P0496 GMC Description

The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the PCM will command the EVAP purge valve open, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent valve open, fresh air will be drawn through the valve and vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge valve into the intake manifold to be consumed during normal combustion. The EVAP system requires the PCM be able to detect a leak as small as 0.040 inch in the EVAP system. The PCM uses several tests to determine if the EVAP system is leaking.

OBDII Code P0496 GMC - Evaporative Emission System Flow During Non-Purge - AutoCodes.com — P0496 GMC Code - Evaporative Emission System Flow During Non-Purge

What does this mean?

What are the Possible Causes of the DTC P0496 GMC?

Faulty EVAP Canister Vent Valve
Faulty EVAP Canister Purge valve
Plugged EVAP canister condition
Faulty EVAP Pressure Sensor
EVAP Canister Vent Valve harness is open or shorted
EVAP Canister Vent Valve circuit poor electrical connection

How to Fix the DTC P0496 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 does this mean?

Code Tech Notes

User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0496 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.

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Information for Specific GMC Models

P0496 2014 GMC Sierra — Evaporative Emission System Flow During Non-Purge
P0496 2015 GMC Sierra — Evaporative Emission System Flow During Non-Purge
P0496 2016 GMC Sierra — Evaporative Emission System Flow During Non-Purge
P0496 2017 GMC Sierra — Evaporative Emission System Flow During Non-Purge
P0496 2018 GMC Sierra — Evaporative Emission System Flow During Non-Purge

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 P0496 GMC Code

1. What are the common symptoms of OBDII code P0496 GMC?

The most common symptoms of code P0496 include the check engine light coming on, a noticeable fuel odor, and a decrease in fuel efficiency.

2. What are the possible causes of OBDII code P0496 GMC?

Potential causes of code P0496 include a loose or damaged gas cap, a faulty purge solenoid valve, a leak in the evaporative emissions system, or a problem with the fuel tank pressure sensor.

3. How can I diagnose the cause of OBDII code P0496 GMC?

Diagnosing code P0496 typically involves inspecting the gas cap for tightness and damage, checking the purge solenoid valve for proper operation, performing a smoke test to detect leaks in the evaporative emissions system, and testing the fuel tank pressure sensor.

4. Can a loose gas cap trigger OBDII code P0496 GMC?

Yes, a loose or improperly sealed gas cap is a common trigger for code P0496. Make sure to tighten the gas cap properly after refueling to see if the code clears.

5. How can I repair OBDII code P0496 GMC?

Repairing code P0496 may involve tightening or replacing the gas cap, replacing the purge solenoid valve, repairing any leaks in the evaporative emissions system, or replacing the fuel tank pressure sensor, depending on the root cause.

6. Is it safe to continue driving with OBDII code P0496 GMC?

While code P0496 may not have an immediate impact on the drivability of your vehicle, it is important to address the issue promptly to prevent potential damage to the emissions system and ensure optimal fuel efficiency.

7. What should I do if OBDII code P0496 GMC keeps coming back after repairs?

If code P0496 persists after repairs, it is recommended to recheck the components replaced or repaired, verify the integrity of the evaporative emissions system, and consider consulting a professional mechanic for further diagnosis.

8. Can a dirty air filter cause OBDII code P0496 GMC?

While a dirty air filter is not a direct cause of code P0496, it can affect the overall performance of the engine and emissions system. It is advisable to regularly replace the air filter to maintain optimal vehicle operation.

9. Will OBDII code P0496 GMC cause a vehicle to fail an emissions test?

Yes, code P0496 can cause a vehicle to fail an emissions test due to the malfunction in the evaporative emissions system, which is designed to control fuel vapors from escaping into the atmosphere.

10. How long does it take to repair OBDII code P0496 GMC?

The time required to repair code P0496 varies depending on the specific cause of the issue, the availability of parts, and the complexity of the repairs. It is advisable to consult a professional mechanic for a more accurate estimate of repair time.