AutoCodes – Jeep – P0491 Jeep

P0491 Jeep Code - Secondary Air Injection System Insufficient Flow Bank 1

Quick Answer

An air pump is used on the vehicle to lower tail pipe emissions on start-up. Common causes include Intake leak, Damaged AIR system components, Faulty AIR Solenoid Valve. 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: P0491 Jeep indicates Secondary Air Injection System Insufficient Flow Bank 1.
Common causes: Common causes include Intake leak, Damaged AIR system components, Faulty AIR Solenoid Valve.
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 594

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 Apr 25, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0491 Jeep Description

An air pump is used on the vehicle to lower tail pipe emissions on start-up. The Powertrain Control Module (PCM) grounds the Air pump relay control circuit which energizes the Air pump. The PCM also grounds the Air combination valve vacuum control solenoid circuit, which energizes the Air vacuum control solenoid. Vacuum is then applied to both Air combination valve diaphragms which opens the shut off valves. The PCM enables both circuits simultaneously when Air system operations id desired. When the AIR system is active, then Air pump forces fresh air into the exhaust stream in order to accelerate catalyst operation. The AIR combination valves replace the conventional check valves. When the AIR system is inactive the shut off valves prevent air flow in either direction.

OBDII Code P0491 Jeep - Secondary Air Injection System Insufficient Flow Bank 1 - AutoCodes.com — P0491 Jeep Code - Secondary Air Injection System Insufficient Flow Bank 1

What does this mean?

What are the Possible Causes of the DTC P0491 Jeep?

Intake leak
Damaged AIR system components
Faulty AIR Solenoid Valve
Faulty AIR system relay

How to Fix the DTC P0491 Jeep?

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 P0491 Jeep 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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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 P0491 Jeep Code

1. What are common symptoms of OBDII code P0491 in a Jeep related to the Secondary Air Injection System Insufficient Flow Bank 1?

- Common symptoms include the check engine light illuminating, rough idling, decreased engine performance, and increased emissions.

2. What are the possible causes of OBDII code P0491 in a Jeep?

- The code P0491 can be triggered by issues such as a faulty secondary air injection pump, a blocked or leaking air inlet or outlet in the system, or a malfunctioning air injection system pressure sensor.

3. How can I diagnose the cause of OBDII code P0491 in my Jeep?

- Diagnosis typically involves checking the secondary air injection pump operation, inspecting for leaks or blockages in the system, and testing the air injection system pressure sensor using a scan tool.

4. Can driving with OBDII code P0491 in a Jeep cause further damage?

- Continuing to drive with code P0491 may lead to increased emissions, reduced fuel efficiency, and potential damage to other components in the vehicle's emission control system.

5. What are some repair tips for resolving OBDII code P0491 in a Jeep?

- Repair tips include checking and replacing the secondary air injection pump, repairing any leaks or blockages in the system, and ensuring proper operation of the air injection system pressure sensor.

6. Is it safe to continue driving my Jeep with OBDII code P0491?

- It is generally not recommended to drive with code P0491 as it can lead to increased emissions and potential damage to the vehicle's emission control system.

7. How much does it typically cost to fix OBDII code P0491 in a Jeep?

- The cost of repairs for code P0491 can vary depending on the underlying issue, but it may range from a few hundred to over a thousand dollars, including parts and labor.

8. Can I reset the check engine light after fixing OBDII code P0491 in my Jeep?

- Yes, the check engine light can be reset using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes after the issue causing code P0491 has been resolved.

9. How often does OBDII code P0491 occur in Jeep vehicles?

- OBDII code P0491 related to the Secondary Air Injection System Insufficient Flow Bank 1 can occur in Jeep vehicles with secondary air injection systems when there are issues with pump operation, leaks, or sensor malfunctions.

10. Are there any preventative measures to avoid OBDII code P0491 in a Jeep?

- Regular maintenance, including checking the secondary air injection system components during scheduled services, can help prevent issues that may trigger code P0491 in a Jeep.