december2022 - A10
CAT CHASE
The real cause of P0420/P0430 DTCs
The 'Catalytic Converter Efficiency' codes might imply a failed converter,
but odds are the ultimate fault lies somewhere else.
By Pete Meier
many P0420/P0430 codes are corrected
without replacing the cat!
If the converter has failed, you also
need to identify what caused the converter
to fail. Sure, age is a factor - but
there are other factors that can result in
premature failure and if left uncorrected,
the new replacement won't last long.
And if it the converter hasn't failed,
you need to determine what caused the
ECM to set the code(s) anyway. False catalytic
converter codes are not uncommon
and in many instances, a reflash is all that
is required to correct the concern.
Start by taking the vehicle for a test
drive. Is there any indication of sluggish
response or low power that might indicate
Common sources of air leaks into the exhaust system that can skew the ECM's tests include damaged
flex pipes and stripped or damaged sensor threads.
T
he " Cataly tic Conver ter
Efficiency " Diagnostic Trouble
Codes (DTCs) P0420 and
P0430, are among the top 10 DTCs
technicians face. And while the
description might imply a failed converter,
odds are the ultimate fault lies
somewhere else.
The catalytic converter is the last stop
for the exhaust gasses generated by the
engine during operation. It is here that the
last remaining pollutants are cleaned up
before finally exiting the tailpipe.
There are three ways a converter
can fail:
Overheated, melted, or a broken
substrate in the converter. This
is usually caused by any factor that
affects the engine's air/fuel mixture
and the resulting feed gasses being sent
to the converter. Even slight variations
10 DECEMBER 2022 VehicleServicePros.com
will cause the converter temperature to
rise significantly.
Converter poisoning: Converter
poisoning means that the substrate has
been coated by a foreign substance and is
no longer exposed to the exhaust stream.
Excessive oil consumption and coolant
leaks past the intake or head gaskets are
common contaminates, as is the improper
use of certain sealants.
Structural
damage: Structural
damage can be physical damage like
dents caused by road debris striking the
housing, stripped oxygen sensor threads,
thermal shock to the converter, and metal
fatigue at mounting points or welds.
HOW TO TACKLE THESE DTCS
When tackling these DTCs, you must
first determine if the converter has truly
failed or not. You'll be surprised at how
After a quick visual, you can use a thermal
imaging camera to " see " the converter in action.
Allow the engine to reach operating temp, and then
check the temp of the converter's front weld ring.
http://www.VehicleServicePros.com
december2022
Table of Contents for the Digital Edition of december2022
Editor's Note: The technician shortage is getting real
Sneak Peek
Most Wanted
Electric vehicles - coming to a shop near you
In Focus
Diagnostic Tech: Using digital tools to reduce the friction of running a shop
Show Me Your Truck: 'Look at that Bad Larry!'
Go Sell Something: Writing a sales pitch
Driving Sales
Tales From the Road: An entrepreneurial spirit
SEMA/AAPEX Wrap-up
Diagnosing Progress
Common diagnostics and trends in hybrid and electric vehicles
Diagnosing faults on modern vehicles
The real cause of P0420/P0430 DTCs
How diagnostic tools cut through the ADAS confusion
When the tools become the tutor
Diagnostic products
december2022 - 1
december2022 - 2
december2022 - 3
december2022 - Editor's Note: The technician shortage is getting real
december2022 - 5
december2022 - Sneak Peek
december2022 - 7
december2022 - 8
december2022 - 9
december2022 - 10
december2022 - 11
december2022 - Most Wanted
december2022 - 13
december2022 - Electric vehicles - coming to a shop near you
december2022 - 15
december2022 - 16
december2022 - 17
december2022 - 18
december2022 - 19
december2022 - 20
december2022 - 21
december2022 - In Focus
december2022 - 23
december2022 - 24
december2022 - 25
december2022 - Diagnostic Tech: Using digital tools to reduce the friction of running a shop
december2022 - 27
december2022 - 28
december2022 - 29
december2022 - Show Me Your Truck: 'Look at that Bad Larry!'
december2022 - 31
december2022 - Go Sell Something: Writing a sales pitch
december2022 - 33
december2022 - 34
december2022 - Driving Sales
december2022 - 36
december2022 - 37
december2022 - Tales From the Road: An entrepreneurial spirit
december2022 - 39
december2022 - SEMA/AAPEX Wrap-up
december2022 - 41
december2022 - 42
december2022 - 43
december2022 - 44
december2022 - A1
december2022 - A2
december2022 - A3
december2022 - Diagnosing Progress
december2022 - A5
december2022 - Common diagnostics and trends in hybrid and electric vehicles
december2022 - A7
december2022 - Diagnosing faults on modern vehicles
december2022 - A9
december2022 - The real cause of P0420/P0430 DTCs
december2022 - A11
december2022 - How diagnostic tools cut through the ADAS confusion
december2022 - A13
december2022 - A14
december2022 - A15
december2022 - When the tools become the tutor
december2022 - A17
december2022 - A18
december2022 - A19
december2022 - A20
december2022 - Diagnostic products
december2022 - A22
december2022 - A23
december2022 - A24
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