P0492 OBD-II Trouble Code: Secondary Air Injection System Insufficient Flow Bank

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0492 code

P0492 is a diagnostic trouble code (DTC) for "Secondary Air Injection System Insufficient Flow Bank". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0492 DIAGNOSTIC Get a fair and transparent estimate upfront

P0492 code definition

Code P0492 indicates that there is a problem with the secondary air injection system, which plays a role in emissions control.

What the P0492 code means

With the P0492 code, it means that the car’s computer has detected a problem with the second bank in the secondary air injection system, which is used to help reduce emissions. Pressure and flow are read through voltage signals sent to the computer, and any variations significantly outside of the automaker’s normal range will trigger this code to be set. Note that the Check Engine Light may or may not illuminate in this instance.

What causes the P0492 code?

A number of potential problems can cause the P0492 code to be set in the car’s computer. These can include:

  • Faulty one-way check valve (most commonly fails in cold weather)
  • Intake leak
  • Faulty relay
  • Blown air injection pump fuse
  • Faulty secondary air pressure sensor
  • Clogged secondary air injection ports in the cylinder head
  • Vacuum leak

What are the symptoms of the P0492 code?

In many instances, the only symptom you’ll notice is the Check Engine Light coming on. However, in other instances, symptoms may include the following:

How does a mechanic diagnose the P0492 code?

First, the mechanic will check the codes stored in the computer using a handheld scanner and clear them. The mechanic will then test drive the car to verify symptoms and to see if the code will set again.

Note that in many instances, an accurate diagnosis can only be made when the engine is cold. The pump operation will need to be verified (when cold) by removing the pressure hose. It will also need to be checked for electrical problems (after being detached from the wiring harness).

The check valve will need to be inspected (when cold). This requires multiple steps, including the removal of vacuum lines, the attachment of a vacuum pump and more, depending on how the valve performs in each step.

A visual inspection for carbon buildup within the cylinder head and/or EGR valve may also be necessary. If buildup is noticed, the head will need to be cleaned out thoroughly. The mechanic should also conduct a thorough visual inspection of all secondary air injection system hoses and lines to check for tears, deterioration, cracking and other problems.

Finally, the intake will need to be checked for leaks. This is most common on the intake manifold gasket.

Common mistakes when diagnosing the P0492 code

One common mistake here is not replacing the check valve. Replacing a pump may fix the problem for a brief time, but if the check valve is faulty and is not replaced, the new pump will fail shortly after installation.

How serious is the P0492 code?

The P0492 code is relatively serious, and it should be diagnosed and repaired quickly. It will eventually have an effect on drivability, as well as on fuel economy. If it results in engine stalling, it could also pose a safety issue.

What repairs can fix the P0492 code?

Multiple repairs may be necessary to repair the P0492 code. The most common repairs are replacement of the pump and the one-way check valve. However, vacuum line leaks will also need to be repaired, and the cylinder head may need to be thoroughly cleaned of carbon build up before the code can be cleared permanently. Replacing the intake manifold gasket may also be necessary if it has developed a leak.

Additional comments for consideration regarding the P0492 code

Diagnosing the cause or causes of the P0492 code can be lengthy, requiring multiple steps and multiple codes cleared after each step.

Need help with a P0492 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

trouble codes
P0492
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0492 code.

SCHEDULE P0492 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(6,144)

Rating Summary
5,685
221
51
35
152
5,685
221
51
35
152

Chris

11 years of experience
13 reviews
Chris
11 years of experience
Ford F-150 - Check Engine Light is on - North Salt Lake, Utah
We were having problems with our check engine light, and Chris was exceptionally thorough until he found the problem and could help resolve the situation. We appreciate having someone who cares enough to get the job done right, not just done. We will definitely use Chris' services in the future. Thanks Chris.

Leng

21 years of experience
2 reviews
Leng
21 years of experience
Mazda MPV - Check Engine Light is on - Seattle, Washington
Leng arrived on time and explained the issue that my van is having. I will make a follow up appointment for the fix. Friendly, easy to talk to, and professional - thank you very much!

Okela

13 years of experience
11 reviews
Okela
13 years of experience
Land Rover LR4 - Check Engine Light is on - Brooklyn, New York
Okela was incredible! He is super thorough and took time to walk us through the issues with our LR4. Couldn’t recommend more! Thank you Okela!!

Robert

37 years of experience
188 reviews
Robert
37 years of experience
Land Rover LR2 - Check Engine Light is on - Atlanta, Georgia
Robert arrived on time. Did a diagnostic check quickly. He was friendly, and gave great service. He knows how to work on a Land Rover.


Related questions

Two mechanics have not been able to repair misfire.

Hi there. Check the intake for a possible vacuum leak around the cylinder 4. If there is no vacuum leak around the cylinder number 4, then there could be a burned valve. Check the compression on all of the cylinders...

More related articles

P2201 OBD-II Trouble Code: NOx Sensor Circuit Range/Performance Bank 1
P2201 code definition NOx Sensor Circuit Range/Performance Bank 1 Related Trouble Codes: P2200: NOx Sensor Circuit Bank 1 P2202: NOx Sensor...
P2534 OBD-II Trouble Code: Ignition Switch Run/Start Position Circuit Low
P2534 P2534 code definition A P2534 trouble code indicates that the PCM has detected a problem in the ignition switch run position circuit. Codes related to a P2534 trouble code include: P2530, P2531, P2532, P2533, P2535, P2536, P2537, and...
P0403 OBD-II Trouble Code: Exhaust Gas Recirculation Circuit Malfunction
P0403 code definition Exhaust Gas Recirculation Circuit Malfunction What the P0403 code means P0403 is an OBD-II generic code that indicates that...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com