P0416 OBD-II Trouble Code: Secondary Air Injection System Switching Valve B Circuit Open

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

SCHEDULE P0416 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0416 code

P0416 is a diagnostic trouble code (DTC) for "Secondary Air Injection System Switching Valve B Circuit Open". 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 for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 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$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0416 DIAGNOSTIC Get a fair and transparent estimate upfront

diagnostic check engine light

P0416 code definition

The powertrain control module (PCM) has detected a problem in the secondary air injection system, which reduces emissions by pumping ambient air into the exhaust stream.

What the P0416 code means

The PCM reads the condition of the secondary air injection system in increments of pressure and flow, which translate to input voltage from sensors. If input readings fluctuate by more than ten percent, a code will be stored and the malfunction indicator lamp (MIL) will illuminate. Some models require multiple drive cycles for the MIL to illuminate, but the code will usually be stored on the initial incident.

What causes the P0416 code?

  • Icing inside the pump in cold weather, due to a failed check valve which allows water or condensation to enter the pump and freeze

What are the symptoms of the P0416 code?

How does a mechanic diagnose the P0416 code?

Usually driven by the serpentine belt, the secondary air injection system uses a pump often called the “smog pump” to inject ambient air into the exhaust stream, reducing emissions. Heat-resistant silicon hoses direct cooler ambient air to the pump, while filtered air comes in through the air filter housing. This cooler air is directed into the exhaust system with silicon and steel lines, with a one-way check valve fitted on each exhaust hose to prevent condensation from backing up into the pump and causing problems. These valves are prone to failure.

Engines that use a V configuration usually feature dual inlet ports in the exhaust pipes and dual one-way check valves from the pump.

  • Test the check valves by attempting to blow air through them from both directions. Air should only flow through the valve in a single direction.
  • If air can flow through the valve in both directions, the valve has failed and should be replaced.
  • Inspect the hoses, lines and fittings for cracking, looseness and deterioration. Replace as needed.
  • If the check valves and lines all appear to be in good shape, perform a visual inspection of wiring, connectors and components. Repair/replace any damaged, disconnected, shorted or corroded parts as needed.
  • Connect a scanner or code reader to the diagnostic connector and record any stored codes.
  • Clear codes and test drive to see if codes return.
  • Check system fuses, referring to service manual for fuse location and values. Replace any blown fuses as needed.
  • After fuses are replaced, operate the secondary air injection system.
  • If fuse continues to blow, inspect for electrical shorts.

Common mistakes when diagnosing the P0416 code

Replacing the secondary air injection pump without devising a water drain on the pump housing can lead to repeated failures of the pump. It’s also essential to test one-way check valves for a proper diagnosis.

How serious is the P0416 code?

A P0416 code can lead to an illuminated MIL and a failed emissions test.

What repairs can fix the P0416 code?

  • Replacement of secondary air injection system pump
  • Replacement of secondary air injection system pump check valves
  • Repair/replacement of lines going to and from secondary air injection system pump

Additional comments for consideration regarding the P0416 code

More often than not, the check valves or the secondary air injection system pump are at fault. Failed check valves can introduce water back into the pump, and in cold weather this can cause the pump to seize or cause other types of catastrophic failure. Diagnosis should start with inspection of the pump and check valves. Other emissions-related codes may accompany a P0416 code, but it’s important to start with these components first.

Need help with a P0416 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
P0416
OBD-II

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

SCHEDULE P0416 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

4.5/5

Number of Reviews

3,696

Rating Summary
3,372
162
42
24
96
3,372
162
42
24
96

Robert

33 years of experience
50 reviews
Robert
33 years of experience
Robert was friendly, very professional and very knowledgeable...he did a wonderful job and went above and beyond. I would highly recommend him!
1999 DODGE DURANGO - CHECK ENGINE LIGHT IS ON - SAN LORENZO, CALIFORNIA

Todd

23 years of experience
2 reviews
Todd
23 years of experience
Very knkwledgeable and timely, great conversation about the car and military life!
2012 CHEVROLET MALIBU - CHECK ENGINE LIGHT IS ON INSPECTION - YORKTOWN, VIRGINIA

Dimitri

7 years of experience
9 reviews
Dimitri
7 years of experience
Very prompt and pleasant. Diagnosed problem in a very short time.
2008 MITSUBISHI ENDEAVOR - CHECK ENGINE LIGHT IS ON - HOUSTON, TEXAS

Brandon

15 years of experience
241 reviews
Brandon
15 years of experience
Very helpful and knowledgeable. Arrived on time and finished on time. Great estimates and information.
2005 NISSAN MURANO - CHECK ENGINE LIGHT IS ON - NORCROSS, GEORGIA

More related articles

How Long Does a Vacuum Brake Booster Check Valve Last?
The braking system on your car requires a lot of pressure. The vacuum booster is one of the main sources of this pressure. This booster will take the pressure that...
Insurance Requirements for Car Registration in Kentucky
The Kentucky Transportation Cabinet requires that all drivers in Kentucky carry liability automotive insurance, or “financial responsibility” in order to operate a vehicle legally and maintain vehicle...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...

Related questions

Q: Check engine light flashing, sucking fuel, procrastinating when accelerating...

This is a very odd set of symptoms. I would suggest ruling out any fuel-related issues as the poor fuel economy and lack of power could be related to faulty sensors like the throttle body sensor, mass air flow sensor,...

Q: How do I know that my OBD system is working right?

The OBD system on your vehicle is a self-monitoring system. The Powertrain Control Module monitors and controls all of the systems and functions that regulate fuel, ignition, emissions, and engine cooling as well as having some minor control over air...

Q: Q: 4WD will not engage

First, if there are any other lights on the dash, (such as the VSC, ABS etc.,) the 4WD module may not allow the 4WD to engage. As for the symptoms that could be causing this condition, it could be: ...

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