P0428 OBD-II Trouble Code: Catalyst Temperature Sensor High (Bank 1)

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

SCHEDULE P0428 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0428 code

P0428 is a diagnostic trouble code (DTC) for "Catalyst Temperature Sensor High (Bank 1)". 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 P0428 DIAGNOSTIC Get a fair and transparent estimate upfront

check engine light

P0428 code definition

The P0428 code is defined as catalyst temperature sensor being high in bank one.

What the P0428 code means

The powertrain control module (PCM) receives a high-resolution signal from the optical sensor which counts pulses on the sensor disk found in the injection pump. This high-resolution signal is extremely important because it has a huge influence on the PCM’s fuel control and timing abilities.

Therefore, a test is regularly run that monitors how many high resolution pulses are not detected. To do this, a comparison is done between the amount of pulses detected since the last pump cam pulse and the amount of pulses that should have happened. Every cam pulse should entail 64 high-resolution pulses.

Basically, this means that the three-way catalytic converter isn’t operating as efficiently as the manufacturer had intended.

What causes the P0428 code?

There are a few main reasons this code may be stored:

  • The catalyst temperature sensor may be malfunctioning.
  • The catalyst temperature sensor harness may be shorted or open.
  • The catalyst temperature sensor circuit is suffering from a poor electrical connection.

Of course, the PCM could simply be faulty too. If it stored this code erroneously, it’s more likely that the wiring it draws information through is damaged, though, as a faulty PCM is extremely rare.

What are the symptoms of the P0428 code?

The symptoms that accompany a P0428 code can be nothing more than a simple Check Engine light coming on. On the other hand, it could be something far more serious like the engine stalling or even refusing to start in the first place.

If the catalytic converter’s performance drops so low that it falls below the predetermined threshold for efficiency or if the code is because of a faulty oxygen sensor, there probably won’t be any drivability issues noticeable to the owner.

That being said, the problem will worsen. The converter could melt or otherwise break internal components, which would lead to engine hesitation, hissing noises during acceleration, poor engine performance and other debilitating conditions.

How does a mechanic diagnose the P0428 code?

A typical diagnosis of the problem should start with the mechanic using the OBD-II scanner to review all the problem codes that have been stored on a freeze frame. Next, the mechanic should check the oxygen sensor and its wiring to make sure that it isn’t simply giving a faulty reading.

Assuming that all checks out, the mechanic will then need to examine the catalytic converter to see if it’s been damaged. This will also mean inspecting the other engine components it could have melted.

Finally, if none of the above reveals the source of the code, the mechanic will want to look into the PCM itself. Although it’s rare, this computer could be to blame.

Common mistakes when diagnosing the P0428 code

By far, the most common mistake a technician makes is simply replacing the catalytic converter and not thoroughly researching what happened to cause the problem. Another problem is not using the OBD-II scanner to check for other issues. Some mechanics will listen to the owner’s report of the problem and immediately know the catalytic converter needs to be replaced without ever addressing the source of the damage.

How serious is the P0428 code?

As we mentioned above, sometimes, there aren’t any noticeable symptoms that coincide with this code being stored. Nonetheless, it’s a serious code because of its potential. Aside from the vehicle simply not being able to start, a faulty catalytic converter can cause a wide range of expensive damage.

What repairs can fix the P0428 code?

There are a few things the technician can do to clear this code:

Additional comments for consideration regarding the P0428 code

An emissions problem stemming from the catalytic converter is going to become a bigger problem for owners living in states where their vehicle has to undergo emissions tests, so it’s important to have this looked at right away.

Need help with a P0428 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
P0428

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

SCHEDULE P0428 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

3,636

Rating Summary
3,315
161
42
24
94
3,315
161
42
24
94

Robert

20 years of experience
128 reviews
Robert
20 years of experience
He is the only mechanic I want to work on my car
2009 CHEVROLET IMPALA - CHECK ENGINE LIGHT IS ON - HUMBLE, TEXAS

Chris

13 years of experience
397 reviews
Chris
13 years of experience
Professional and excellent. Highly recommended, no nonsense guy.
2002 DODGE RAM 2500 VAN - CHECK ENGINE LIGHT IS ON - SAN FRANCISCO, CALIFORNIA

Jonathan

19 years of experience
304 reviews
Jonathan
19 years of experience
I have used Jon several times now and won't use anyone else. I highly recommend him [so long as he doesn't get so busy he isn't available when I need hem ;-) ].
2005 CHRYSLER PT CRUISER - CHECK ENGINE LIGHT IS ON - WESTMINSTER, COLORADO

Ben

38 years of experience
883 reviews
Ben
38 years of experience
He was great will use him for every
2007 MERCEDES-BENZ SLK350 - CHECK ENGINE LIGHT IS ON - HOUSTON, TEXAS

More related articles

P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...

Related questions

Q: Q: Car shut off while driving

Without additional information, it is hard to say what could have caused this. Your car has a variety of sensors that can cause it to shut down depending on whether or not everything is functioning correctly. I would suggest having...

Q: Check Engine light on and car not accelerating.

Hello. Providing those codes does help quite a bit. It appears that you have a few issues going on. From what I see it looks like you have a failure in the throttle position sensor and in the fuel pump...

Q: Car turns on and off. The brake and the steering wheel gets harder.

Hello, thanks for writing in. The P0171 is an indication of a lean mixture, which can be caused by an air leak in the intake (as you were advised), a borderline engine temp sensor reporting a warmer engine temperature than...

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