P2438 OBD-II Trouble Code: Secondary Air Injection System Air Flow/Press Sensor Circuit High Bank 2

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P2438 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P2438 code

P2438 is a diagnostic trouble code (DTC) for "Secondary Air Injection System Air Flow/Press Sensor Circuit High Bank 2". 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 P2438 DIAGNOSTIC Get a fair and transparent estimate upfront

P2438 code definition

A P2438 trouble code means that the PCM has detected a problem within the secondary air injection system. Another component that can cause a P2438 code to be stored is a problem with the pressure sensor circuit. Bank 2 refers to the bank of the engine that does not contain the first cylinder.

Some other trouble codes often associated with a P2438 code are: P2430, P2431, P2432, P2433, P2434, P2435, P2436, P2437, P2439, P2440, P2441, P2442, P2443, P2444, P2445, P2446, and P2447.

What the P2438 code means

A P2438 trouble code usually is an indication of a variation in the input voltage reading to the PCM of greater than 10 percent. Sometimes, though, a vehicle has to experience this condition during multiple cycles in order for the Check Engine light to be illuminated, though the code is usually stored on the initial failure.

What causes the P2438 code?

A common cause of a P2438 trouble code is a bad check valve in the air inlet hose of the secondary air injection pump. This code most often happens during cold weather, with the check valve allowing condensation from the exhaust system to enter via the injection pump. This moisture freezes during cold weather, causing the secondary air injection pump to bind up, causing a catastrophic pump failure or an overloaded circuit in the form of a blown fuse. Another cause is electrical wiring and connectors getting burnt up by engine exhaust that is hotter than normal.

What are the symptoms of the P2438 code?

In addition to a stored trouble code and illuminated Check Engine light, symptoms of a P2438 trouble code include:

How does a mechanic diagnose the P2438 code?

To diagnose a P2438 trouble code successfully, a mechanic needs an advanced scanner and a digital volt/ohmmeter. The best way to diagnose a P2438 trouble code includes:

  • Inspecting the air inlet hose check valve. If air flows both ways through the valve, then the check valve is bad and needs replacing.

  • The mechanic should also do a visual scan of all secondary air injection pump wiring, connectors, and components.

  • After repairing or replacing wiring, connectors, and components, the mechanic needs to retest the system to ensure everything is in working order.

  • After clearing the P2438 trouble code, the mechanic should then perform a test drive to check if the trouble code returns.

Common mistakes when diagnosing the P2438 code

Mechanics must check the one-way check valve within the air inlet hose to make sure the problem does not lay there. Otherwise, pump replacement can still result in further pump failure as the check valve allows moisture to build up in the pump, causing a failure when the moisture freezes once again during cold weather.

How serious is the P2438 code?

A P2438 trouble code, if not dealt with before cold weather arrives, can cause the secondary air pump to fail due to moisture freezing with it, causing it to bind up. This, in turn, can cause higher-than-normal engine exhaust emissions.

What repairs can fix the P2438 code?

To fix a P2438 trouble code, the mechanic must follow certain steps, including:

  • Inspecting and replacing any damaged or worn wiring, connectors, or components.

  • In addition to shorts and damage to wiring and connectors, a mechanic needs to inspect all secondary air injection system hoses and fittings for any cracking, breaking, or heat damage from higher than normal engine exhaust heat.

  • Replacing or repairing any damaged hoses or components.

  • A mechanic should also check any fuses associated with the secondary air injection system to make sure that they are not blown. If blown, the mechanic should replace the fuses.

  • Retest the system as needed upon making the necessary repairs or replacing any blown fuses.

  • If for some reason a fuse continues to blow, the mechanic should check the secondary air pump to make sure it is not damaged or failing.

  • If the secondary air pump failure is the cause, it should be repaired or replaced it as necessary.

Additional comments for consideration regarding the P2438 code

A failure to replace a one-way check valve can lead to failure due to contaminants entering any replacement pump. The mechanic can prevent this by replacing any faulty one-way check valves they find.

Need help with a P2438 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
Check Engine Light
P2438

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P2438 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

4,743

Rating Summary
4,361
185
47
28
122
4,361
185
47
28
122

Oreste

12 years of experience
108 reviews
Oreste
12 years of experience
Nissan Altima - Check Engine Light is on - Hialeah, Florida
Showed up quick, and went straight to inspecting a brake light on the dash issue. He found the issue, fixed it, and showed me exactly what was wrong. Thank you!

Daniel

9 years of experience
58 reviews
Daniel
9 years of experience
Honda Fit - Check Engine Light is on - Chicago, Illinois
Told me everything I needed to know and switch out after the inspection. So, I scheduled another service the next day for all the fixes, or fluid maintenance.

Patrick

31 years of experience
1032 reviews
Patrick
31 years of experience
Hyundai Santa Fe - Check Engine Light is on - Austin, Texas
Even after working on my car, he took the time to explain what he did, the parts, and any next steps. Very knowledgeable!

Joe

12 years of experience
22 reviews
Joe
12 years of experience
Toyota 4Runner - Check Engine Light is on - Sacramento, California
Joe was very thorough in his inspections, and his knowledge & experience was clear in his explanations of what was wrong with my car. I really appreciated his recommendations, and the fact that he worked so efficiently that it cut down on time... I would definitely book with him again.

More related articles

The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore. You may want to check out the Ethnology Museum, or the Southern...
Veteran and Military Driver Laws and Benefits in Idaho
The The state of Idaho offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch in the past, or are current active military members. Vehicle registration benefits Disabled veterans with a...
What are the Car Pool Rules in Hawaii?
Hawaii Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all states, freeways are an integral part of life...

Related questions

KOEO test code 332

Hello there, A few different things can cause insufficient EGR flow. The most likely are: a stuck closed EGR valve a failed EGR valve solenoid faulty oxygen sensor low fuel pressure exhaust leak These can also...

CEL purge valve manifold

Hello there, thank you for asking about your 2011 Mercedes-Benz C63 AMG. If you are suspicious, you may want to hire another facility for a second opinion. Each time the Check Engine Light was illuminated, there's a good chance the...

Vehicle turns off at any rpm, at idle or highway speeds, without stumbling or warning.

This kind of a stalling issue can be caused by a variety of problems. They are typically caused by ignition faults, wiring faults, and fuel issues. Although you do not have a Check Engine Light on, you should still scan...

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.

1-800-701-6230 · hi@yourmechanic.com