P0419 OBD-II Trouble Code: Secondary Air Injection System Relay B Circuit Malfunction

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

SCHEDULE P0419 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0419 code

P0419 is a diagnostic trouble code (DTC) for "Secondary Air Injection System Relay B Circuit Malfunction". 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 P0419 DIAGNOSTIC Get a fair and transparent estimate upfront

check engine light

P0419 code definition

The P0419 trouble code means that the secondary air injection system relay B circuit is malfunctioning.

What the P0419 code means

The vehicle’s PCM (powertrain control module) has detected an issue with the secondary air injection system. This system is essential for reducing emissions. It pumps in ambient air and channels it into the engine exhaust.

Changes in secondary air injection system flow and pressure are measured by the PCM in increments of input voltage. Any readings that fall outside of the manufacturer’s predetermined range of acceptable flow by greater than 10% will generally trigger the P0419 code being stored.

What causes the P0419 code?

There are a few reasons that this code could be stored by the PCM. The most common one, though, is that the weather is simply too cold. The secondary air injection pump has a one-way check valve that is designed to protect it thanks to an air inlet hose. However, this check valve can malfunction. When it does, it allows condensation from the exhaust to get into the pump. In cold weather, it will freeze.

This ice binds inside the secondary air injection pump leading to catastrophic failure or blowing the fuse.

Another reason is from temperatures on the other end of the spectrum. High temperatures in the engine exhaust can burn the electrical connectors and wiring.

What are the symptoms of the P0419 code?

There are a handful of symptoms to look out for:

  • Abnormal sounds coming from the secondary air injection system
  • Engine stalling
  • Engine idling after starting
  • Engine hesitation when accelerating

The Check Engine Light should usually come on too, but in some models, the problem has to be detected at least a couple times before this will happen.

How does a mechanic diagnose the P0419 code?

To diagnose the problem, an experienced mechanic will do some combination of the following:

  • Use an OBD-II scanner to find all the trouble codes a vehicle’s PCM has stored
  • Next, they’ll inspect the pump for signs of condensation.
  • Finally, they’ll examine the wires to see if the PCM is simply receiving erroneous readings.

In some cases, the mechanic may also need to look at the air bypass solenoid harness to see if it’s shorted or open or otherwise suffering from a bad electrical connection as well.

Common mistakes when diagnosing the P0419 code

Before a mechanic considers replacing the secondary air pump, they should fabricate a water drain on its housing. Otherwise, there’s a good chance of future pump failure occurring.

It’s also critical that they test the one-way check valves during the diagnosis process. This is often overlooked.

How serious is the P0419 code?

This is a pretty serious code that represents a problem which needs to be addressed right away. While the issue with the secondary air injection system isn’t going to prove to be fatal, it does mean the vehicle is underperforming in a number of ways. If nothing else, this code is going to cost the owner when they go to the pump. It could also make it nearly impossible to drive the automobile if the engine keeps stalling or having other problems.

What repairs can fix the P0419 code?

More often than not, the pump simply needs to be replaced or repaired. As we mentioned earlier, this code is very common in cold weather where condensation can keep the secondary air injection system from working correctly.

Otherwise, the mechanic may simply need to fix wires that have become damaged or corroded and which are, therefore, giving the PCM bad readings.

Additional comments for consideration regarding the P0419 code

If frozen condensation is found to be the underlying problem behind the P0419 code being stored, then the mechanic needs to look for other areas this moisture could be affecting as well. Even without a trouble code to document it, the vehicle may be suffering because of ice elsewhere as well.

Need help with a P0419 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
P0419

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

SCHEDULE P0419 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

3,936

Rating Summary
3,597
169
44
25
101
3,597
169
44
25
101

Abdul

8 years of experience
279 reviews
Abdul
8 years of experience
After using a local mechanic and DIY techniques to pass emission inspection, I turned to yourmechanic.com again. Abdul came to my home and inspected my vehicle. Within an hour, he inspected and performed major repair. He tested his work to confirm accuracy, and he cleaned up any debris. Great job! I am still grateful for this service and the professional, knowledgeable mechanics.
2007 TOYOTA CAMRY - CHECK ENGINE LIGHT IS ON - SMYRNA, GEORGIA

James

28 years of experience
423 reviews
James
28 years of experience
James was early for the appointment. He was extremely courteous and thorough. He had a very great attitude and was friendly I appreciate all of his work
2003 FORD EXPEDITION - CHECK ENGINE LIGHT IS ON - SANFORD, FLORIDA

Vladimir

7 years of experience
214 reviews
Vladimir
7 years of experience
Vladimir knew what he was doing very confident in diagnosis
2003 AUDI A4 QUATTRO - CHECK ENGINE LIGHT IS ON - SACRAMENTO, CALIFORNIA

Cyrus

32 years of experience
45 reviews
Cyrus
32 years of experience
Very informative & helpful thank you 
2010 CHEVROLET CAMARO - CHECK ENGINE LIGHT IS ON - ATLANTA, GEORGIA

More related articles

P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem...
P0291OBD-II Trouble Code: Cylinder 11 Injector Circuit Low
P0291 code definition When your vehicle’s PCM registers the P0291 code, it means that a voltage reading came from the fuel injector circuit – for cylinder number 11’s fuel injector –...
P0684 OBD-II Trouble Code: Glow Plug Control Module to PCM Communication Circuit Range/Performance
P0684 code means there is a failing connection within the Glow Plug Control Module often due too corroded wires and solenoid failures.

Related questions

Q: obd trouble code p0014 , hard up shifting

Hello. The P0014 code and hard up shifting condition is a common problem on this engine. Typically, it is either the solenoid, or the connection on the solenoid. If both of those have been replaced, then the exhaust cam...

Q: Q: Car runs hot

The Check Engine Light may have more to do with the engine than the temperature condition. The engine would need to be checked to see if the radiator is flowing coolant properly, and not partially clogged. The thermostat should be...

Q: Air bag deploying

There have been many cases of defective airbags or systems causing a fault code to be stored in the system computer. If there is a fault code stored, the air bag will not deploy because the system has been shut...

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